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A. Suggestions for Improving Bone Marrow Aspirations

To make bone marrow collections run more smoothly and efficiently, so that the large number of requests for bone marrows can be accommodated:

1. Decide who will do the bone marrow in advance. If you need assistance, contact the fellow on the Hematology Service or a senior hematologist. Instruction should be completed before the bone marrow is started, not during the marrow collection.
2. Schedule the bone marrow in advance with the Hematology Lab. Early scheduling increases the chance of a desirable time slot. Bone marrows are scheduled from 0815-1100 hrs, Monday and Thursday, 0815-1000 hrs Tuesday, and 0815-1500 hrs, Wednesday and Friday. Emergency marrows at other times must be approved by the Laboratory Medicine resident on duty; scheduling depends on technical coverage in the laboratory. If the procedure is canceled, please notify the laboratory by telephone.
3. Also schedule the bone marrow with the Ward Clerk, and order a bone marrow tray and a bone marrow needle (Rosenthal or Jamshidi) from Central Supply. The patient should not be scheduled for other procedures at the same time. Order a CBC, reticulocyte count, differential, and platelet count to be drawn on the day of the bone marrow.
4. Inform the patient about the procedure and obtain informed consent well in advance of the technologist's arrival at the bedside.
5. About 15 minutes prior to the time of the appointment, begin to position and "prep" the patient (it can take that long just to get the patient into the proper position). You will need sterile rubber gloves, an iodophor or tincture of iodine, lidocaine and tape, in addition to the bone marrow tray and needles, in the patient's room with you. The patient should be completely "prepped" and the lidocaine should have been injected prior to the technologist's arrival.
6. If marrow collection is delayed more than 10 minutes, the procedure must be rescheduled.

B. Emergency Processing of Bone Marrow Samples for Histologic Examination

Fixed specimens will be prepared for storage in Hematology until routine processing by Histopathology. Questions concerning processing by Histopathology during non-routine times should be directed to the Anatomic Pathology Resident on duty.

C. Bone Marrow Culture

Marrow specimens for culture are collected during the bone marrow aspiration/biopsy procedure and submitted by the Hematology Section of the Clinical Laboratories.

Routine bacterial culture of the marrow is not superior to routine blood culture, and is not offered except for sterility checking prior to transplantation as described above. Candida spp. and cryptococci also grow well in routine blood culture, and marrow culture is not recommended for these organisms.

Blood is the recommended specimen for CMV antigen testing. The test is not standardized for bone marrow.

If infection with Brucella, Histoplasma or Mycobacterium spp. are diagnostic considerations, 1.5 mL of marrow should be submitted in a yellow top Isolator tube (available from Hematology) and the organism(s) of interest specified on the request slip.

Submit requests for culture on the white microbiology requisition identifying the type of specimen, the procedure(s) requested, and the collection time. Indicate the patient's diagnosis, special conditions (e.g., immunocompromised, transplant, cystic fibrosis, etc.), and any antimicrobial therapy. This information helps in the proper processing of the specimen and in the interpretation of the culture. Additional charges are incurred for identification and susceptibility testing.

Hours: Cultures are planted and Gram stain smears are read between 0800 and 2330 hrs, 7 days a week. Outside of these hours, bacterial cultures are inoculated and Gram stains made of specimens from normally sterile (including operative) sites, e.g., CSF, by Hematology, but only if ordered stat. Other specimens, e.g., urine, sputa or swabs in transport media, are not processed at night but are held until regular laboratory hours.

GENERAL:

Most specimens submitted for culture should be refrigerated until brought by messenger to the laboratory. Do not, however, refrigerate blood cultures, cerebrospinal, joint and other normally sterile body fluids, cultures in which fastidious organisms (e.g., gonococci in joint fluid) are suspected, or cultures which have already been inoculated onto plated media. Such cultures should be brought to the main Clinical Laboratories for prompt incubation.

Label each specimen with patient's name, unit number, source, date, and time.

ABSCESS: see WOUND

AMNIOTIC FLUID:

Collection: Collect the fluid with a syringe, expel any excess air, and submit the syringe capped with a Luer plug. When fluid is not available, swab the area and submit the swab - a much less desirable specimen - in transport medium for bacterial culture.

Bacteria (routine): Indicate type of collection (amniocentesis, Caesarian, vaginal) on requisition. When specimen is collected by amniocentesis or during Caesarian section, aerobic and anaerobic cultures are performed. Only aerobic cultures are performed on specimens obtained during vaginal delivery.

Viruses: For CMV and HSV submit fluid specimen in syringe or swab specimen with cells in viral holding medium. For rubella culture, consult the laboratory.

ASCITIC FLUID: see PERITONEAL FLUID

BLOOD:

Bacteria (routine): The yield of blood cultures in adults is volume-dependent and increases approximately 3% per mL of blood cultured; 20% of bacteremic adults have less than 1 colony-forming unit in 10 mL of blood. About 80% of patients who have positive blood cultures are positive on the first sampling, 90% are detected with two samplings, and nearly 99% with three samplings; optimal routine blood culture consists of 2 or 3 sets of aerobic and anaerobic bottles with 10 mL of blood in each bottle. Do not collect more than three blood cultures from a single patient within a 24 hr period.

1. Sites and Timing of Collection and Blood Volume Needed
   It is best to not draw blood cultures within hours to days after administering antibiotics and if possible to avoid collecting the sample(s) from indwelling intravascular catheters or shunts, which are often externally contaminated, especially at 3-way stopcocks which are difficult to disinfect. To avoid dilution of the specimen by the infused fluids, draw specimens distal to existing intravenous lines. Never draw from a line unless specifically authorized to do so by the physician. Blood cultures should not be used to follow effectiveness of antiobiotic therapy.
   
   Adults:
   • Always collect 2 sets of cultures from different sites.
   • Peripheral draws are preferred.
   • At least one draw should be from a peripheral site.
   
   Children:
   • Draw one culture of at least 1 mL in an aerobic bottle, and at least 0.5 mL in an anaerobic bottle.
   • The anaerobic bottle may be omitted in neonates, if there is insufficient sample and it is not warranted by the clinical presentation.
   • Check with the physician for the amount of blood which can be safely withdrawn from the patient, up to the maximum of 10 mL per bottle.
   
   
2. Peripheral Blood Culture Draw (includes DTTP instructions)
3. Central Line Blood Culture Draw (includes DTTP instructions)

Special bacterial culture: For Brucella spp. special collection containers and culture technique are required. Contact the laboratory for instructions.

Fungi: Yeasts such as Candida spp. and cryptococci will grow in routine blood cultures and do not require a separate "fungal culture." To culture Histoplasma capsulatum, a biphasic fungus, collect two dark green top (gel-free) sodium heparin tubes for a separate culture. For all other fungi, including Aspergillus and similar molds, a tissue sample is required as no growth will be seen on blood culture.

Mycobacteria culture: Routine culture of blood for mycobacteria is unproductive except in patients who are HIV-positive. A special blood culture to detect organisms of the Mycobacterium avium-intracellulare complex is available for HIV-positive patients. Submit 5 ml blood in a Dark green (gel-free) sodium heparin tube and note the diagnosis on the requisition.

Parasites including Malaria: Blood submitted in a lavender top tube is examined by Giemsa stain for bloodborne parasites: Plasmodium, Trypanosoma, Babesia, visceral Leishmania and microfilaria spp. Review the patient's history for possible periodicity and an optimal time of sampling. Note the time of sample collection on the requisition.

Viruses: Indicate the clinical situation and the virus sought. An antigenemia asssay can assist in the diganosis of viremia due to cytomegalovirus in immunocompromised patients. Submit 6 ml blood in a lavendar top EDTA tube. CMV antigen is done only from 0700 - 1430 hrs on Monday - Friday. Specimens submitted after the deadline must be recollected the next day. In neonates, culture for enterovirus is also performed on request. Submit two green top sodium heparin tubes for separation of the buffy coat. The minimum blood volume for this procedure from a neonate is 0.5 ml.

BODY FLUID (e.g., Joint, Pericardial, Pleural; see also AMNIOTIC, CEREBROSPINAL, or PERITONEAL FLUID):

Collection: Collect 15-20 mL of fluid with a syringe, expel any excess air, and submit the syringe capped with a Luer plug. Fluid collected in a sterile, clear plastic black top tube is less satisfactory for anaerobic culture.

BONE MARROW:

Collection: Bone marrow specimens for culture can be collected independently or during a diagnostic bone marrow aspiration and biopsy procedure; schedule the latter in advance by calling Hematology.

Bacteria (routine): Routine bacterial culture of the bone marrow supplies no additional information beyond that obtained from the routine blood culture and is not offered, except for sterility checks of donor bone marrow before transplantation.

Brucella: Submit a 1.5 mL Isolator yellow top tube, obtained from Hematology.

Fungi: For Histoplasma capsulatum submit bone marrow for culture in 1.5 mL Isolator yellow top tube. Candida spp. and cryptococci will grow in routine blood cultures and bone marrow culture is not recommended.

Mycobacteria: Submit the sample in a 1.5 mL Isolator yellow top tube, obtained from Hematology.

Viruses: Blood should be submitted instead of bone marrow for CMV antigen. The test is not standardized for bone marrow.

BRONCHOALVEOLAR LAVAGE and LUNG BIOPSY:

CATHETER TIP:

Collection: Submit intravascular or intra-articular tip in sterile tube. DO NOT SUBMIT IN TRANSPORT MEDIUM. Catheter tips should always be accompanied by a set of blood cultures drawn from a vein (not from the catheter) for proper evaluation of catheter-related sepsis. Catheter site cultures submitted on swabs are not predictive of catheter infection, but can be useful to determine the causative agent when localized site infection is apparent and a purulent specimen can be obtained. Urinary or peritoneal catheter tips are not appropriate for culture; send the urine or peritoneal fluid instead.

Bacteria (routine): The tip is rolled on the surface of a blood plate; counts of >15 colonies suggest colonization of the catheter and a possible role for the device as a source of bacteremia. Cultures will detect aerobic bacteria and yeast.

Fungi: Routine bacterial culture will detect yeast. Notify the laboratory if Malassezia furfur infection is suspected on specimens from hyperalimentation patients.

CEREBROSPINAL FLUID:

Collection: Submit in sterile tube for bacterial culture (use the tube included in the LP kit or a sterile, clear plastic black top tube.

Bacteria (routine) (2 mL): Because of the relative fragility of many of the common etiologic organisms in meningitis, the fluid should be incubated at 37°C until plated at the laboratory. At night submit the CSF promptly and it will be placed in an incubator - in the absence of antimicrobials, CSF is an excellent culture medium.

Cryptococcus neoformans: Cryptococcal antigen (1 mL) testing is performed daily at 1000 hrs; additional tests will be done until 2100 as needed for patient care. Order a Cryptococcus culture, submitting at least 2 mL of CSF.

Coccidioides immitis: If coccidioidomycosis is suspected order the immunodiffusion serological test. Antibody is present in serum in >90% of cases of meningitis, but is found in the CSF only 70% of the time. Culture for this organism can be done when specifically requested, but is only about 30% sensitive; submission of at least 30 mL of CSF increases the diagnostic yield. Request cryptococcus culture and "look for cocci."

Mycobacteria: CSF will be processed for AFB culture only after consultation with the laboratory. Smears are positive in less than 25% of culture-positive spinal fluids, and are only performed when the index of suspicion is high. Because the number of organisms in TB meningitis is usually quite low, even when the fluid is turbid, a large volume of spinal fluid should be submitted for culture, preferably at least 30 mL. Mycobacterial culture of a clear acellular spinal fluid is unproductive and should not be ordered.

Parasites (Naegleria, Acanthamoeba, Trypanosoma, Toxoplasma): Consult the laboratory immediately when diagnosis is suspected and deliver specimen to laboratory within 30 min of collection. Culture is possible only if patient is not on antibiotic therapy. Rapid diagnosis may be possible by examination of Giemsa stain or wet mount and/or phase contrast microscopy.

Viruses (identify the specific agent[s] sought):

Arbovirus: Contact laboratory for information about collection of specimens for diagnosis of mosquito-borne encephalitis. Requests are forwarded to the Viral and Rickettsial Disease Laboratory of the California Department of Health Services, and must be accompanied by a special referral form which includes the relevant clinical history.

Cytomegalovirus: PCR for CMV is indicated to diagnose the cause of polyradiculopathy or encephalitis when CSF neutrophilic leukocytosis is unexplained by bacterial infection. Consult with lab before ordering test.

Enterovirus: Positive cultures of CSF in CNS infection caused by enterovirus are 40-70% sensitive, depending on how early in the disease the culture is performed. Stool (rectal swab) and throat cultures increase the likelihood of culturing the virus.

Herpes simplex: Culture of CSF to diagnose HSV is insensitive. Detection of HSV DNA by PCR is preferred (sensitivity 99%). Consult with the Infectious Disease service before ordering the test.

Varicella-Zoster: VZV virus occasionally causes encephalitis in normal persons, usually in association with skin lesions, and in HIV-infected patients. PCR of CSF for VZV is suggested for patients with possible CNS disease. Consult with the Infectious Disease service before ordering the test.

CERVIX/ENDOCERVIX: see VAGINA/CERVIX

COLONIC and OTHER INTESTINAL (e.g., Duodenal) ASPIRATES and BIOPSIES (see also GASTRIC ASPIRATE):

Collection: Submit aspirate or biopsy specimens in a plastic cup with a tight fitting lid. Keep the tissue moist, but do not put it into transport medium.

Parasites: For Giardia, Strongyloides, and other intestinal parasites, deliver specimen to laboratory within 30 minutes of collection on Monday-Friday. For Giardia, stool antigen detection by EIA is more sensitive and specific than microscopic examination. Proctoscopic exam for E. histolytica is seldom performed. A series of at least 3 routine stool examinations for parasites should be performed on each patient before sigmoidoscopy examination is done. Aspirate or scrapings from suspicious colonic lesions can be submitted in SAF fixative with 1 part sample to 3 parts of SAF. Consult the laboratory prior to collecting the specimen. Lesion biopsy specimens should be examined by routine histopathology. Serology for E. histolytica is quite useful, particularly in diagnosing amebic liver abscess.

Viral culture: For CMV and Herpes simplex, place biopsies in viral holding medium.

CONJUNCTIVAE: see EYE

DIALYSIS FLUID: see PERITONEAL FLUID

DRAINAGE: see WOUND

EYE:

Collection: Conjunctival scrapings are obtained and collected with a cotton swab on an aluminum wire shaft and placed in transport tube appropriate to the test requested: transport medium for bacterial culture, viral holding medium for viruses, and chlamydial holding medium for Chlamydia.

Bacteria (routine): If submitting cultures from both eyes, be sure to note which sample is from the right or left eye.

Chlamydia trachomatis: Conjunctival scrapings are required to diagnose chlamydial conjunctivitis.

Parasites: For Acanthamoeba spp., consult the Proctor Foundation Laboratory (x64584) when the diagnosis is suspected. For Loa Loa, send specimen to Anatomic Pathology.

Viruses: Request virus culture for enterovirus and adenovirus.

GASTRIC ASPIRATES and BIOPSIES:

Collection: Gastric aspirate specimens should rapidly be brought to the laboratory, 0630-2330 hrs, for neutralization of the antibacterial acid content.

Bacteria (routine): Gastric samples will be cultured for Helicobacter pylori when specified. The culture of gastric contents may perhaps be useful to diagnose neonatal sepsis; the routine laboratory examination of these specimens includes a search for group B streptococci and Listeria monocytogenes, as well as less common pathogens. Blood and amniotic fluid cultures are more sensitive and more specific for diagnosing group B streptococcal infection than culture of gastric aspirate.

Mycobacteria: Culture of gastric contents is usually less productive than sputum or other respiratory cultures. First morning gastric aspirates are most useful for diagnosing tuberculosis when the patient is unable to produce sputum.

JOINT FLUID: see BODY FLUID

NASOPHARYNGEAL SPECIMENS:

Flocked swab in Universal Transport medium is the primary method for nasopharyngeal specimen collection for VIRAL testing.

NASOPHARYNGEAL SWAB (FLOCKED SWAB):

Collection: Use flocked swab/Universal Transport Medium for collection. Insert swab into the nostril, gently rotating the swab inward until resistance is met at the level of the turbinates. Rotate the swab a few times against the nasopharyngeal wall (approximately 10 sec) and then withdraw swab.  Insert swab into container with Universal Transport Medium. Break end of swab so top of vial can be screwed on securely. Appropriately label specimen and send to the laboratory with a completed Microbiology requisition.

Respiratory viruses: Nasopharyngeal flocked swabs in universal transport medium are the preferred specimen type for respiratory virus testing. Antigen tests for Influenza, Parainfluenza, Adenovirus, and RSV are routinely performed in place of culture. Sensitivity of the antigen test is approximately 80-90% as compared to culture. If clinically indicated, respiratory virus PCR may be ordered when antigen test is negative with Infectious Disease approval.

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NASAL ASPIRATE or WASH:

Collection: Specimens for virus isolation or pertussis PCR should be collected within 5 to 7 days after onset of illness and preferably in the first 4 days. Specimens collected after 7 days rarely yield a pathogen.

To obtain a nasal aspirate from a young child or infant, attach one end of a Sim tip to a De Lee mucus trap (both available from Material Services) and the other end to wall suction (do not employ mouth suction!). Gently thread the tube through the anterior nares into the nasopharynx and aspirate material at a pressure of 80 mm Hg as the tube is withdrawn. Clear the tubing of aspirated material by suctioning with non-bacteriostatic saline, if necessary. Tie off the tubing and immediately deliver the specimen to Microbiology.

Nasal washings should be submitted only if a nasal aspirate cannot be obtained. A sterile disposable pediatric ear syringe bulb can be used to instill 1-3 mL of sterile, non-bacteriostatic saline into the nostril. Rotate the supine infant or child onto one side, gently express the saline from the bulb into the open nostril and immediately aspirate the liquid back into the bulb with a rapid squeeze/release action. Transfer the aspirated contents of the bulb into an empty sterile tube. For cooperative older patients, instill 2-3 mL of sterile saline into each nostril while the head is tilted slightly backwards. Ask the patient to tilt the head forward while holding a clean container beneath the nose to catch the draining liquid. Then transfer the drainage into an empty sterile tube.

Bordetella pertussis: Submit nasal aspirate or wash for PCR.

PERICARDIAL FLUID: see BODY FLUID

PERITONEAL FLUID (including Ascitic and Dialysis Fluid):

Collection: Collect 15-20 mL of fluid with a syringe, expel any excess air, and submit the syringe capped with a Luer plug for smears and cultures. Fluid collected in a sterile, clear plastic black top tube is less satisfactory for anaerobic culture.

Bacteria (routine): Includes cultures to isolate aerobic and anaerobic bacteria, Candida and Aspergillus.

Other organisms: Order "Other Fungal Culture" if histoplasmosis is being considered, and/or mycobacterial culture if peritoneal tuberculosis is a diagnostic consideration.

PLEURAL FLUID: see BODY FLUID

PUS (see also WOUND):

Collection: Submit in the same manner as tissue or collect in a syringe, expel any excess air, and submit the syringe capped with a Luer plug. A tissue specimen is preferred to a specimen of pus, but pus is a better sample than swabs submitted in transport medium.

SPUTUM and TRACHEAL ASPIRATE:

Collection: Specimens are collected by direct expectoration into a clean, plastic cup capped with a lid which does not leak (a clean, non-sterile container is satisfactory). Sputum induction, if needed, must be arranged with Respiratory Therapy, usually the day prior to collection. Luken traps may be submitted. If possible, the patient should rinse out gross oral contamination from the mouth with freshly obtained water before attempting to expectorate a sputum sample.

Bacteria (routine): Specimens are Gram-stained upon arrival in the laboratory. Samples demonstrating a large number of squamous cells as evidence of pharyngeal contamination will not be processed further and the nursing unit will be asked to submit a new, properly collected specimen.

Fungi: Order culture for "Aspergillus" if suspected. Candida spp. often contaminate the respiratory tract and are only evaluated from lung transplant patients and from other patients in whom they are found to be numerous and in pure culture. When systemic infection with Histoplasma, Coccidioides, Blastomyces, or the agents of mucormycosis is suspected, order "Fungal Culture". Specimens collected by more invasive procedures, such as bronchial lavage, have a better yield in detecting these organisms. Mark the appropriate box for the desired agents. KOH is routinely included as part of Fungal culture.

Mycobacteria: A first morning sputum (at least 5 mL) refrigerated promptly until sent to the laboratory is most suitable for mycobacterial cultures; 24-hour sputum cultures are not performed. Expectorated first-morning sputum is generally more likely to give positive culture results, but culture of sputum induced by heated aerosol is probably as good or better than culture of randomly obtained gastric contents. Because of the possibility of intermittent excretion of the organism, multiple cultures should be submitted. Positive smears are reported by telephone.

Parasites: Refer samples for Pneumocystis carinii to Cytology. For Strongyloides or Paragonimus, specify the organism sought,

Viruses: SPUTUM is not an appropriate specimen.

Herpes simplex: Because HSV is frequently excreted asymptomatically, sputum is a poor specimen for the diagnosis of HSV pneumonitis. See Bronchoalveolar lavage above.  

Respiratory viruses: For tracheal aspirates, Direct FA is done routinely to detect antigens of Influenza and Parainfluenza viruses, Adenovirus, and RSV.

SKIN (see also WOUND):

Collection: Tissue obtained by biopsy is often the best specimen for the diagnosis of skin infections, but aspirated or drained pus, vesicular fluid, or skin scrapings may be useful for the diagnosis of some infections.

Bacteria (routine): For erysipelas, impetigo, and cellulitis swabs taken from superficially crusted and weeping lesions, when present, should be submitted in transport medium. Needle aspiration of the center or the margin of the area involved is of limited utility in these infections.

For paronychia, whitlow, folliculitis, and carbuncles, submit the aspirated pus or - less desirable - submit the purulent drainage on a swab in transport medium.

Fungi: For ulcerated and/or nodular fungal skin infections (sporotrichosis, blastomycosis, or infections due to Cryptococcus spp.), submit a skin biopsy from the margin of the lesion in parallel with a specimen submitted to Dermatopathology for histologic examination. For superficial mycoses (e.g., Candida, Epidermophyton, Trichophyton, or Microsporum spp.) submit skin scrapings, hair, or nails in a clean test tube for KOH preparation and fungal culture.

Mycobacteria and Nocardia spp.: For ulcerated and/or nodular skin lesions due to acid-fast organisms (e.g., Mycobacterium marinum, Nocardia asteroides) submit a skin biopsy for mycobacterial culture in parallel with a specimen submitted to Dermatopathology for histologic examination.

Parasites: Skin biopsies can be cultured for Leishmania spp.; call Microbiology prior to submitting the samples so that reagents can be prepared ahead. Smears of aspirates or touch preparations are stained with Giemsa and examined microscopically. Wet mounts from skin snips from the buttock, calf, or area over the scapula can be examined to diagnose filarial (onchocercal) infection; this test is not useful for the diagnosis of cutaneous larval migrans. Tissues should be submitted to Dermatopathology for histologic examination for parasites.

Viruses:

Herpes simplex: Submit a swab taken from an intact fluid-containing vesicle; rub the swab across the base of the lesion to collect cells. Dried crusts from older lesions are unsuitable. Use a cotton swab on a wire shaft to collect the specimen and submit the swab to the laboratory in Viral Holding Medium; wooden shafts may contain compounds which are toxic to the virus. To obtain a sample suitable for direct examination with fluorescent antibody, scrape the base of an opened vesicle with a sterile scalpel blade and transfer the cells obtained onto two clean glass slides, making two spots on each slide, each approximately 1.5 cm. in diameter (the size of a dime). Let the slides air-dry and submit them for staining. See also Varicella-zoster below.

Varicella-zoster: Direct antigen testing is the most effective means of detection, and can also be used for Herpes simplex. To obtain a sample suitable for direct examination with fluorescent antibody, scrape the base of an opened vesicle with a sterile scalpel blade and transfer the cells obtained onto two clean glass slides, making two spots on each slide, each approximately 1.5 cm. in diameter (the size of a dime). Let the slides air-dry and submit them for staining.

STOOL:

Collection: Collect a fresh specimen in a clean, plastic cup with lid that does not leak (a non-sterile container is satisfactory). Deliver in <1 hr to the laboratory between 0630 and 2330 hrs. Fresh stool for laboratory testing should not be submitted between 2330 and 0630 hrs when the Microbiology laboratory is closed because of the toxicity of stool for the etiological agents of disease. Outpatients should obtain instructions and containers from the laboratory, from the outpatient phlebotomy stations, or from the Emergency Department. For samples requiring a preservative, the method of preservation is described below with the test description.

Bacteria (routine): Fresh stool should be submitted within 2 hr of collection. Do not refrigerate. Recovery of Shigella is probably improved if the specimen is brought to the Laboratory within 15 minutes of collection. Vials containing Cary-Blair transport medium are available for bacterial culture of stool specimens which cannot be delivered to the laboratory within 2 hrs of passage, and can be obtained from the outpatient phlebotomy stations, or from the Emergency Department. Fill these containers only up to the red line. Stool specimens give better recovery rates for enteric pathogens than do rectal swabs. Two specimens collected 48 hrs apart are sufficient for the detection of the great majority of cases; a greater number of specimens require consultation with the laboratory. Swabs should be submitted in Cary-Blair preservative.

Nosocomial acquisition of stool pathogens is extremely uncommon. If bacterial enteritis is suspected, stool cultures should be requested upon admission to the hospital: they will not be accepted routinely on patients who have been hospitalized for >3 days. Contact the laboratory for exceptions.

Specimens are routinely cultured for Salmonella, Shigella, Aeromonas, Edwardsiella, Plesiomonas, and Campylobacter spp. If Yersinia, E. coli 0157, or vibrios (Vibrio cholerae or V. parahaemolyticus) are suspected, order culture for these agents separately. Please inform the laboratory if cholera is suspected so that special media can be prepared.

Clostridium difficile toxin: Fresh stool should be submitted before 1500 hrs, since toxin is unstable in stool prior to inoculation, and cytotoxin assays are inoculated daily at 1700 hr.

Fecal WBCs: Select a sample of diarrheal stool with an applicator stick, including the bloody or mucous discharge if present. Because WBCs lyse in old specimens, the specimen should be brought to the laboratory within 3 hours of collection. This test lacks sensitivity and specificity to diagnose cause of hospital-acquired diarrhea and is only done on outpatients and in patients <72 hrs post admission.

Fat Globules, Qualitative Smear for: Submit unpreserved stool. Only useful in patients over 6 months of age.

Fungi: Test not offered.

Mycobacteria: Test not offered.

Parasites ("O & P"): Submit stool in SAF (Sodium Acetate-Acetic Acid-Formalin) vials for preservation of stool to be examined for the presence of ova and/or parasites (available from Microbiology - L553, the outpatient phlebotomy stations, and the Emergency Department). Follow the instructions which accompany the vials. Fill to the red line only. Patients should not have received antimicrobial therapy or barium contrast medium for at least 7 days prior to sample collection.

 

Cryptosporidium: Routine ova and parasite examination includes a screening test for Cryptosporidium. If the routine O & P examination is negative for Cryptosporidium and infection is still suspected, order a Cryptosporidium Concentrate, which will detect low numbers of the organism.

Giardia lamblia: Submit fresh stool or stool in SAF or Cary-Blair medium. The antigen test is preferred to Ova and Parasite Examination if Giardia is the only intestinal parasite in the differential diagnosis; it is offered instead of the "String" test.

Nosocomial acquisition of parasites is even more uncommon than nosocomial shigellosis. If parasitic enteritis is suspected, O & P examinations should be requested upon admission to the hospital; they will not be accepted routinely on patients who have been hospitalized for >3 days. Contact the laboratory for exceptions.

Microsporidium: Order separately from routine Ova and Parasite exam.

Pinworm: Collect 3 swube paddles from 3 consecutive mornings. Collect each specimen BEFORE defecation or bathing. Collection paddles are available from outpatient phlebotomy stations or from Microbiology. If these paddles are unavailable, transparent, clear Scotch tape (not Magic Mending tape) can be used for collection and applied sticky side down to a clean glass microscope slide.

Viruses: The agents of viral gastroenteritis are generally not cultivable, including Adenovirus 40 and 41, Norwalk agent and Rotavirus. Enterovirus culture: Stools are cultured for enteroviruses only to aid in defining the cause of aseptic meningitis and/or neonatal viral sepsis. Please provide clinical information, including diagnosis, on the requisition. Place an amount of the stool specimen the size of a pea in viral holding medium. Rectal swabs are less satisfactory for virus isolation and should only be submitted if it is impossible to obtain a stool specimen; leave the swab in the holding medium.

Rotavirus antigen: A test for Rotavirus antigen assay by EIA is available to diagnose diarrheal disease in pediatric patients. Submit fresh stool in a plastic cup.

THROAT:

Bacteria (routine): Submit dacron swab in paper wrapper. Unless a search for a specific organism or diagnosis is requested (e.g., diphtheria, gonorrhoea, pertussis, staphylococcus carriage, thrush), throat cultures are routinely processed only to exclude the possibility of group A streptococcal pharyngitis.

Fungi: see Bacteria (routine) - specify a diagnosis of possible thrush.

Viruses: Refer to tracheal aspirate or nasal washing for appropriate collection of specimens for respiratory viruses. Throat swabs are acceptable specimens for Enterovirus culture to diagnose the causative agent of aseptic meningitis.

TISSUE (see also WOUND):

Submit in an anaerobe transport vial (available in the operating rooms), a sterile plastic cup with a tightly fitting lid, or in a clear plastic sterile black top tube. For anaerobic culture, also rub the cut surface of the tissue immediately using two dacron swabs on plastic white shafts and submit these swabs in Amies charcoal transport medium. Clearly indicate on requisition that the swabs are from the tissue and are for the anaerobic culture. Do not place the tissue itself in the charcoal transport medium.

TRACHEAL ASPIRATE: see SPUTUM

URETHRA:

Collection: Wipe the urethra clean and preferably collect specimen >1 hr after urination

Bacteria: "Milk" the urethra and collect the discharge (if no discharge is present, follow the specimen collection instructions below for Chlamydia spp.). Place the collection swab in Amies charcoal-containing transport medium and submit it to the laboratory within 6 hours of collection.

Chlamydia trachomatis: Collect the chlamydia specimen after collecting the specimen for gonococcus culture. For Chlamydia by DNA detection (not approved for medicolegal purposes, which demand culture), use the BD ProbeTec male (blue) Mini-tip collection kit. Insert the swab 2-4 cm into the urethra and rotate for 15-30 seconds to obtain an adequate sampling of intact cells. Place the swab into the empty plastic transport tube. For culture, transport a cotton-tipped swab in Chlamydia Holding Medium. Obtain collection/transport materials for DNA detection or culture from the Microbiology Laboratory. The DNA detection test is designed only for genital specimens (urethral, urine or endocervical), not for rectal or other nongenital specimens (e.g., conjunctivae); submit a swab in Chlamydia holding medium for culture of nongenital specimens.

URINE:

Collection: The culture should be refrigerated promptly and should not sit at the patient's bedside at room temperature.

1. Clean-voided urine for culture is collected in a clean, dry plastic cup with a non-leaking lid (non-sterile containers are OK):

   Females: While the labia are held apart with the aid of a pair of sponges, the vulva is thoroughly washed from front to back with two successive cotton pledgets or sponges soaked in soap. Special attention should be paid to the urethral meatus (benzalkonium, chlorhexidine or hexachlorophene should not be used, as contamination of the collection with residual disinfectant can sterilize the urine sample before it reaches the laboratory). Then two additional spongings with sterile water or saline are used to rinse the vulva, and the specimen is passed into a plastic screw-capped cup. The patient should not halt and restart the urinary stream for a "midstream" collection, but preferably should move the container into the path of the already voiding urine.

   Males: The process is similar to that described above. The foreskin is retracted, and the glans penis is thoroughly washed with two successive cotton pledgets or sponges soaked in soap, special attention being paid to the urethral meatus. Then additional successive pledgets with sterile water or saline are used to rinse the glans.

2. Indwelling catheter urine is collected by aspirating the urine through the catheter port using a sterile vacutainer tube with a red stopper ("plain, sterile"). Alternatively, the urine can be collected using a needle and syringe, and transferred to a red stopper vacutainer tube (pop the top of the vacutainer tube; there is no need to go through the rubber diaphragm with a needle). Do not send urine obtained from the long drainage tube or a collection bag.

3. The first collection immediately after insertion of a catheter is considered a "straight cath urine." Straight catheter urine is collected using catheter collection kits. Urine is placed in screw-capped cup.

4. Foley catheter tip cultures are unsuitable for the diagnosis of urinary infection and are not accepted for processing.

Bacteria (routine): Quantitative culture is performed on all urine specimens. Gram stains are performed only on request. A single culture is adequate in a clinical situation requiring rapid institution of therapy. There is no need for repeat specimens to be submitted at daily or other frequent intervals.

Reports of genital flora mixed with other organisms in amounts >1000 colony-forming units (CFU)/mL will be accompanied by a notation such as "Mixed flora present. Suggest recollection if clinically indicated". Mixed flora are not routinely identified unless the specimen was properly collected from a catheter or nephrostomy tube. If a culture yields one organism, the organism will be identified. If two or more organisms are present they will be identified according to an algorithm that takes into account the clinical setting and total bacterial count in the urine. Susceptibility tests are routinely performed only if >10,000 CFU/mL are found in midstream urine or if >1000 CFU/mL are present in specimens obtained by catheter, ureterostomy, or nephrostomy drainage. A physician desiring a different procedure on a specimen should contact the laboratory.

Screening Culture: By checking the box on the requisition "Omit organism ID and susceptibility" one can request a screening culture, a less expensive quantitative culture for which species identification and susceptibility testing will only be performed (at an additional charge) if specifically requested after results are reported. Plates from positive urine screening cultures are saved for 7 days. This test is particularly appropriate for screening of children, pregnant women, young women with first UTIs, and patients on Foley catheter drainage.

Chlamydia trachomatis by DNA detection: Collect the first 15-20 mL of voided urine; do not dilute this critical portion of the sample collection by submitting a larger volume of urine.

Fungi: Order Yeast culture on the requisition when urinary tract infection with these organisms is suspected. Consult with the laboratory prior to submission of urine when infection with other fungal agents is suspected.

Mycobacteria: The best urinary specimen is the first morning void, which is approximately an 8-hour specimen held under conditions usually free of other bacteria. Twenty-four hour urine cultures are not performed because overgrowth with contaminants is a frequent cause of unsuccessful acid-fast culture. Specimens should be collected by a "clean-voided" technique (see above).

Because tuberculosis of the urinary tract is extremely uncommon in our patient population, urine cultures for mycobacteria require consultation with the laboratory. Cultures are generally restricted to patients with positive PPDs who are found to have unexplained pyuria with negative routine bacterial cultures. Urine cultures should not be used to detect cases of pulmonary tuberculosis. Urinary specimens are not routinely smeared because they are rarely positive, and nonpathogenic mycobacteria which are morphologically similar to M. tuberculosis are frequently present in the genitourinary tract.

Parasites: Urine collected between 1000 and 1400 hrs can be examined for Schistosoma haematobium and (rarely) microfilariae.

Viruses:

CMV: Urine for CMV culture will generally be accepted only on children <7 years old and transplant patients known to be CMV-seronegative prior to transplantation. At least 20 mL urine in a screw capped container should be submitted for best results, although as little as 1 mL is acceptable.

Adenovirus, BK (papovavirus), mumps, measles, rubella: Requests for isolation of these viruses from the urine, except adenovirus and mumps, require consultation with the laboratory; indicate the specific virus sought.

VAGINA/CERVIX:

Collection: Use a speculum without lubricant (the lubricant can be toxic to the cells and microorganisms of interest). Wipe the cervix clean of vaginal secretions and mucus.

Bacteria: Collect the endocervical exudate on a dacron swab with a rotating motion. Place the swab in Amies charcoal-containing transport medium and submit it to the laboratory within 6 hrs of collection.

Gonoccoci only cultures, as indicated on the microbiology requisition, will be done only on Thayer-Martin medium and will be examined only for Neisseria gonorrhoeae. These cultures will not be examined for other potential pathogens.

If culture for Neisseria gonorrhoeae and other potential pathogens is indicated, mark the Aerobic only box on the requisition and when possible indicate what potential pathogens are of concern. Potential pathogens include beta-hemolytic streptococci, Gardnerella vaginalis, Staphlococcus aureus, large numbers of yeasts and gram-negative rods, and Haemophilus species in men, etc.

Vaginal cultures of pregnant women for group B streptococci should be ordered as Beta-strep only cultures.

Bacterial vaginosis/vaginitis: Order Gram stain and submit two smears of vaginal secretions on labeled slides. Microscopic examination of a Gram-stained smear of vaginal secretions can disclose both "clue" cells, consistent with a diagnosis of bacterial vaginosis, and yeasts.

Chlamydia trachomatis: NOTE: some spermicidal agents and feminine powder sprays interfere with tests for Chlamydia infection. Collect the chlamydia specimen after obtaining the culture specimen for gonococcal infection. For Chlamydia by DNA detection (not approved for medicolegal purposes, which demand culture), use the BD ProbeTec female (pink) collection kit for endocervical specimens. First remove excess mucus from the cervical os with the large-tipped cleaning swab and discard. Then insert the small-tipped swab into the cervical canal and rotate for 15-30 seconds firmly to obtain cervical cells. Uncap the Diluent tube and fully insert the small-tipped swab into this tube. Break the shaft of the swab at the score mark. Tightly recap the tube containing the swab. For culture, transport a cotton-tipped swab in Chlamydia Holding Medium. Obtain collection/transport materials for DNA detection or culture from the Microbiology Laboratory. The DNA detection test is only for genital specimens (urethral, urine or endocervical), not for rectal or other nongenital specimens (e.g., conjunctivae); submit a swab in Chlamydia holding medium for culture of nongenital specimens.

Herpes simplex: Gently clean the surface of an intact genital vesicle with saline. Aspirate the vesicular fluid with a tuberculin syringe and needle and place the fluid obtained in Viral Holding Medium. Alternatively, unroof the vesicle and collect the fluid contents with a cotton swab on a wire shaft, then submit the swab to the laboratory in Viral Holding Medium; wooden shafts may contain compounds which are toxic to the virus. To obtain a sample suitable for direct examination with fluorescent antibody, scrape the base of an open vesicle with a sterile scalpel blade and transfer the cells obtained onto two clean glass slides, making two spots on each slide, each approximately 1.5 cm. in diameter (the size of a dime). Let the slides air-dry and submit them for staining.

Serogroup B streptococcus: For optimal sensitivity, obtain selective broth medium from Microbiology. Swab the lower vagina and rectum, and submit the swabs to the laboratory in the medium. Alternatively, submit the swabs in Amies charcoal-containing transport medium.

Trichomonas vaginalis: Collect secretions from high in the vaginal canal. For best results place the collected fluid into an InPouch® (available from Microbiology from 0630-2330 hrs, and in the Emergency Department) and deliver the specimen to the laboratory. For additional details see the Test Table section of the Laboratory Manual.

Yeast: see Bacterial vaginosis above. Gram stain will readily detect clinically active vaginal yeast infection. Culture is generally unnecessary unless isolation of the organism is required for susceptibility testing in cases of treatment failure.

WOUND (including Abscess and Drainage; see also SKIN and TISSUE):

Collection: A tissue specimen is preferred to a specimen of pus, but pus is superior to swabs submitted in transport medium.

Send the tissue specimen in a plain, black screw-capped sterile tube or a sterile cup, NOT in Amies charcoal transport medium. A small piece of tissue from the edge of an infected wound will give better information than superficial sampling with a swab.

When purulent material is available, the pus itself should be submitted rather than a swab containing a scant specimen. Sending pus is an excellent means of maintaining anaerobiasis of samples while they are being transported to the laboratory.

When during surgery the operative findings suggest anaerobic infection, such as the presence of a putrid odor or foul discharge, place an aspirate of the infected area in an anaerobic transport vial (these containers are available in the Operating Room only). Alternatively, collect 20 mL or more of fluid with a syringe, expel any excess air, and submit the syringe capped with a Luer plug.

When neither tissue nor sufficient pus or fluid is available, send at least two dacron swabs in Amies charcoal transport medium; a backup broth for detection of very small numbers of organisms cannot be inoculated if only one swab is sent.

Bacteria (routine): Includes procedures to isolate aerobic and anaerobic bacteria. Anaerobic cultures can only be performed from swabs if the swabs are submitted in transport medium. Anaerobic cultures are not done on specimens from skin or specimens from the Dermatology clinic, unless specifically requested.

Fungi:

Candida and Aspergillus: Cultures for these pathogens should be specifically requested when their presence in abscesses and superficial wounds is suspected. Tissues and fluids from normally sterile sites are automatically examined for both yeast and Aspergillus.

Other species: When other, mycelia-forming fungi are suspected, the optimal sample is a biopsy of the involved tissue. Cultures are held for 30 days. Swabs are unacceptable specimens for culture of mycelia-forming organisms, particularly organisms such as those causing mucormycosis, because they frequently fail to yield the pathogen seen in and grown from biopsies.

Mycobacteria: Wound cultures for mycobacteria are infrequently indicated and are not performed from swab specimens. If Nocardia spp. are suspected, order nocardia culture or mycobacterial culture, which can detect Nocardia spp.

Parasites: see Skin

Viruses: Request testing for the specific viruses of clinical interest. Tissue from infected areas should be collected aseptically and transported to the laboratory in viral holding medium.

Cytomegalovirus: Tissues can be cultured for CMV but the distinction between shedding of CMV (carriage) and active disease is difficult to make.

ORGANISMS CONSISTENT WITH NORMAL FLORA

• various gram-negative bacteria other than salmonella, shigella, campylobacter, aeromonas, yersinia, edwardsiella and vibrio species
• non-dextrose-fermenting gram-negative rods enterococci
• Staphylococcus epidermidis
• alpha-hemolytic and nonhemolytic streptococci
• diphtheroids
• Staphylococcus aureus in small numbers
• yeast in small numbers
• anaerobes in large numbers

• Any amount of the following:
  1. corynebacterium species
  2. lactobacillus species
  3. alpha-hemolytic and nonhemolytic streptococci
  4. nonpathogenic neisseria species
• The following when mixed and not predominant:
  1. enterococci
  2. enterobacteria and other gram-negative rods
  3. Staphylococcus epidermidis
  4. Staphylococcus aureus
  5. Gardnerella vaginalis
  6. candida species and other yeasts
• Anaerobes (too many species to list) - the following are reported
  1. when predominant or in pure growth:
  2. prevotella species
  3. clostridium species
  4. peptostreptococcus species

• Any amount of the following:
  1. diphtheroids
  2. nonpathogenic neisseria species
  3. alpha-hemolytic streptococci
  4. Staphylococcus epidermidis
  5. nonhemolytic streptococci
  6. anaerobes (too many species to list; varying amounts of bacteroides species, anaerobic cocci, diphtheroids, fusobacterium species, etc.)
• Lesser amounts of the following when accompanied by the above:
  1. yeasts
  2. haemophilus species
  3. pneumococci
  4. Staphylococcus aureus
  5. gram-negative rods
  6. Neisseria meningitidis

• Staphylococcus epidermidis
• Staphylococcus aureus (in small numbers)
• micrococcus species
• nonpathogenic neisseria
• alpha-hemolytic and nonhemolytic streptococci
• propionibacterium species
• small numbers of other organisms (e.g., candida or acinetobacter species)

Routine susceptibility testing is performed by the microtiter broth dilution technique (in special situations, the single disk diffusion [Bauer-Kirby] method may be used). Susceptibility testing and reporting formats provide both numerical and interpretive reports of the minimum inhibitory concentration (MIC) of each drug tested. The MIC, the lowest concentration of a drug that inhibits the growth of the organism in vitro, is reported in mg/L (µg/mL).

Varying batteries of drugs are employed, one optimized for gram-negative bacilli, and a second for gram-positive cocci. The tables on the following pages give the composition of the batteries, the range of concentrations tested in two-fold increments, and the interpretive breakpoints. The system is continuously adjusted in response to new information and current needs. Further susceptibility testing is not performed unless the clinical circumstances suggest the unusual instance of a resistant organism (approval required), or the patient is allergic to penicillins and cephalosporins, in which event please call the laboratory.

Susceptibility tests will routinely be set up on any organism judged potentially significant by the laboratory, if the test has not been performed on the same organism within 7 days (4 days for Pseudomonas aeruginosa, Citrobacter, Enterobacter, and Serratia spp.). Normal flora not usually associated with pathogenicity in the site from which recovered, and rare organisms in a culture containing numerous normal flora or a predominant pathogen are not routinely tested. The plates from significant cultures are held in the lab for 7 days after the final report is sent to the ward. Thus it is possible to consider obtaining susceptibilities after the report is received.

A. Conditional Reporting of Antimicrobial Susceptibility

In conjunction with the Pharmacy and Therapeutics Committee and the Infectious Disease Service, the Microbiology section of the Clinical Laboratories has developed a heirarchical scheme of reporting antimicrobial susceptibility test results. The intent of conditional reporting is to reduce the use of the more costly or toxic antimicrobials in instances where they are not needed, and thus decrease the enormous costs of antimicrobial usage at UCSF.

Susceptibility results will be reported for a panel of primary drugs consisting of standard, less expensive (often generic), and less toxic agents. If organisms are resistant to these primary drugs, additional results will be reported for more expensive, potentially more toxic drugs of second choice. This procedure follows the general principles set forth by the Clinical and Laboratory Standards Institute, and has been recommended by the UCSF Antibiotic Advisory Subcommittee of the Pharmacy and Therapeutics Committee.

Drug panels have been devised for staphylococci, streptococci (enterococci and pneumococci), enterobacteriaceae, Pseudomonas aeruginosa, and salmonella and shigella, and take into account whether the isolates are from urine or from other sites. Primary drugs are always reported; secondary drugs are reported only if resistance is found to the specific primary drug. These panels and the conditionally reported secondary drugs are described below:

If a suitable primary or secondary drug is unavailable, testing against appropriate additional antimicrobial agents can be undertaken on request. Consult the laboratory.

B. Criteria for Susceptibility

The interpretations of the susceptibility test results are defined as follows:

S- Susceptible: The organism is inhibited by the antimicrobial at a concentration readily achieved in blood and urine with the usual dosing.

I- Intermediate (or indeterminate): Higher doses of the antimicrobial than usual may be required to achieve an inhibitory serum concentration. An interpretation of I for anti-pseudomonal penicillins suggests only that the drug should not be used as a single agent, but should be employed in combination with an aminoglycoside.

R- Resistant: The organism is not inhibited by the antimicrobial, even at concentrations achievable in serum or in urine using high doses.

All penicillin G-susceptible staphylococci are tested for the presence of beta-lactamase (penicillinase). Results of this test are reported separately. THE DRUG OF CHOICE FOR STAPHYLOCOCCI THAT DO NOT PRODUCE BETA-LACTAMASE IS PENICILLIN G - IT IS THE MOST POTENT AND THE LEAST EXPENSIVE.

Staphylococcus saprophyticus are not routinely tested. Urinary tract infections with this organism respond to antimicrobial agents such as nitrofurantion, TMP SMZ, or a fluoroquinolone at concentrations achieved in urine in patients with normal renal function. Contact laboratory for susceptibility testing in cases of treatment failure or allergy.

Enterococci are always resistant to methicillin-like drugs, cephalosporins, and trimethoprim plus sulfamethoxazole, and have until recently had predictable MICs to penicillin G, ampicillin, piperacillin and vancomycin. Strains of enterococci have been found to be resistant to these penicillins and vancomycin. E. faecium resistant to penicillins by a non-beta-lactamase mechanism have been detected at this Medical Center. Even when in-vitro testing shows susceptibility to penicillins and vancomycin, these latter antibiotics should be combined with an aminoglycoside for the treatment of endocarditis and probably of other life-threatening infections. If enterococci are the only organisms isolated from a normally sterile site (e.g., blood, CSF), they are routinely tested for inhibition by ampicillin and vancomycin and by 1000 mg/L of streptomycin or 500 mg/L of gentamicin. Susceptibility to a high concentration of an aminoglycoside alone correlates well with a synergistic bactericidal effect of ordinary serum levels in combination with penicillin G, ampicillin or vancomycin when the organism is sensitive to the latter drugs.

Other important gram-positive pathogens (e.g., listeria) give an essentially predictable susceptibility pattern.

C. Antimicrobial Susceptibility Patterns

Current information regarding the cumulative percentage of commonly isolated bacterial species which are susceptible to a given level of antimicrobial and the number of strains in the UCSF data base can be found at www.ucsf.edu/idmp/. The data include isolates from both community-acquired and nosocomial infections which have met the laboratory criteria for potential clinical importance (e.g., urine >=100,000/mL, isolates from otherwise sterile areas such as blood, predominant organisms from a wound, etc.). However, not all the bacteria unequivocally represent clinically significant infections (e.g., S. epidermidis).

Ag = antigen detection
bDNA = branched DNA
C = culture
FA = fluorescent antibody
H = histology
PCR = polymerase chain reaction
S = serology
++++ = likelihood of positivity

The Quality Assurance section is responsible for coordinating an ongoing quality control program for the Clinical Laboratories and for implementing and monitoring the compliance of the Clinical Laboratories with all legal requirements.

Clinical Laboratories reference ranges for quantitative assays are determined using the 95th percentile. At least one standard and two controls are included in each run for every test, whenever possible. Quantitative controls utilize a 2 standard deviation (95%) confidence limit. We participate in the CAP Proficiency Testing Programs. Additional performance specifications are available upon request.

Temperatures of all applicable equipment are monitored, instrument performance is calculated and recorded on a scheduled basis, reagents are parallel-tested, preventive maintenance schedules are maintained on all equipment, and method evaluations are performed as required.

In Chemistry, Hematology and Immunology, results of controls are charted daily, and monthly calculations of standard deviation are performed and analyzed for accuracy and precision of the procedures.

In Hematology, in addition to the use of commercial controls, a computer program detects instrument drift by mean calculations from patient results of MCH, MCHC, and MCV. Five patient samples are also held over each day to be run on the following day for comparison.

The Blood Transfusion Service is accredited by and maintains the standards of the American Association of Blood Banks. All test cells and antisera are evaluated daily to demonstrate their capacity to detect weakly reactive antigenic determinants and weak antibodies. Each unit of blood is inspected daily, as well as just prior to issue, for abnormal color or appearance. Temperatures of blood storage refrigerators are maintained at 1-6°C and are monitored continuously by both audible and visible signals.

In Microbiology, all media, reagents, and stains are checked for reactivity at preparation and at regular intervals. Blind as well as labeled unknowns are sent through the laboratory regularly.

In Immunology, in addition to the use of controls, all reagents are checked before use for proper reactivity.

Statistical evaluations are performed on new lots of controls, standards, reagents, methods and changed equipment before they are put into use.

Reference (Outside) Laboratories:

Before an agreement is set up with a reference laboratory for performing tests not offered by the Clinical Laboratories, information on CLIA certification, licensure (as applicable), test methodology, references, normal ranges and quality control are sent to the Quality Assurance Section. An option is also provided for submitting Quality Control specimens to these laboratories to evaluate their performance.

House Staff Laboratories

Laboratory facilities for use by the house staff are not provided by the UCSF Clinical Laboratories. Any laboratory facilities on nursing units or in clinics are maintained and supplied by those units. (See Point of Care Testing)