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Lab Manual for UCSF Clinical Laboratories

Lab Manual for SFGH

Internal Resources

Obtaining Patient Specimens (Blood and Timed Urine Collections)


Go directly to Collection of Urine Specimens.


  1. OBTAINING THE SPECIMEN

For specific information about individual tests refer to the Alphabetical List of Tests section of the manual. The following information is helpful for obtaining any specimen submitted to the clinical laboratory. For 24 hour urine collection guidelines, see section V, below. See also the Pediatric Blood Specimens section for specific information regarding obtaining blood specimens from pediatric patients and a list of minimum blood requirements.


Instructions for obtaining specimens for particular tests, tube type, and the amount of specimen required are included in the Alphabetical List of Tests section. The amount listed is the amount that is adequate for obtaining accurate test results. Every effort should be made to obtain the required amount of specimen.


  1. CONTAINERS USED FOR LABORATORY SPECIMENS

The container to be used in collecting a specimen for individual tests is specified in the Alphabetical List of Tests section of this manual. Use only containers with “in-date” expiration dates. To ensure that the specimen is routed immediately to the appropriate laboratory area, use the correct container and provide the specified amount of specimen for each test.


  1. TRANSPORTING LABORATORY SPECIMENS

All containers of patient specimens must be protected by plastic or similar bags during transportation to the laboratory. The requisition must be placed in the outside pocket of the bag. Do not staple the requisition to the bag.


  1. BLOOD SPECIMEN TUBES


PLASTIC TUBE TOP COLOR AND ORDER OF DRAW CHART


Please use the correct tube type to ensure accurate results. Measuring potassium on a sample using potassium EDTA as the anticoagulant will be inaccurate, as will measuring calcium on a specimen containing EDTA, which chelates calcium. Oxalate inhibits several enzymes, including LD, and acid phosphatase. Do not mix the contents of different tubes to avoid cross-contamination with tube additives. Small volume pediatric tubes (1.8 mL light blue top) should be used for pediatric patients, and patients with difficult veins.


A. Order of Draw: The following order is recommended when drawing several tubes during a single venipuncture to avoid test result error due to cross-contamination from tube additives, according to the National Committee for Clinical Laboratory Standards (NCCLS, document H3-A5):


1. Blood culture tube or blood culture bottles


2. Light blue top coagulation tube


4. Gold top serum tube with clot activator/serum separator


5. Plain red serum tube with clot activator


6. Royal blue top serum tube for trace metals


7. Light green with lithium heparin and gel separator; dark green lithium heparin, without gel; bright green sodium heparin, without gel separator


8. Pink top plasma tube for blood bank; white top (PPT) with separator; tan top for blood lead; lavender top tubes – all containing EDTA preservative


9. Gray top plasma tube with glycolytic inhibitor


B. A description of blood specimen tube types, including size of the tube, maximum volume of blood drawn, contents (preservatives, anticoagulants or clot activator, recommended times to invert tubes to facilitate mixing of the sample, and comments follows:


Light Blue Top Tube, 2.7 mL whole blood draw volume. Contains 0.3 mL of 3.2% (109 mM) buffered sodium citrate to chelate calcium, preventing coagulation. Invert gently 3 – 4 times to mix. Tube must be filled completely for tests requiring plasma, mainly coagulation studies.


Light Blue Top Tube – for pediatric use, 1.8 mL whole blood draw volume. Contains 0.2 mL of 3.2% (109 mM) buffered sodium citrate. Invert gently 3 – 4 times to mix. Tube must be filled completely.


Gold Top Gel (SST) Tube, 13 x 100 mm, 5 mL. Contains silica particles on tube walls that act as clot activator, and a gel separator. Invert 5 times to mix. Use for chemistry and serology determinations requiring serum.


Red Top (non gel) Tube, 13 x 100 mm, 6 mL. Does not contain preservative, gel separator, or anticoagulant. Silica particles on the tube wall act as clot activator. Invert 5 times to mix. Use for certain reference laboratory tests. Not acceptable for Transfusion Service (Blood Bank) specimens.


Royal Blue Top Tube Trace Metals. 13 x 100 mm, 6 mL. Does not contain preservative, gel separator, or anticoagulant. Silica particles on the tube wall act as clot activator. Invert 5 times to mix. For trace element studies such as copper and zinc.


Light Green Gel (PST) Tube, 13 x 100 mm, 3.5 mL. Contains 59 USP units of lithium heparin and gel separator. Invert 5 times to mix. Used for STAT chemistry tests, troponin, liver and metabolic panels, ammonia.


Dark Green Top (non gel) Tube, 13 x 75 mm, 3 mL. Contains 51 USP units of lithium heparin. Invert 8 – 10 times to mix. Use for ionized calcium, methemoglobin when not ordered as part of arterial blood gas.


Bright Green Top (non gel) Tube, 13 x 100 mm, 6 mL. Contains 86 USP units sodium heparin. Invert 8 – 10 times mix. Use for Mycobacteriology (AFB) culture, and for bone marrow bacterial, fungal and mycobacteriology cultures.


Pink Top Tube, 16 x 100 mm, 10 mL. Contains 18 mg of K2EDTA (sprayed on) to chelate calcium, preventing coagulation. Invert 8 – 10 times to mix. Use only for the Transfusion Service (Blood Bank) testing. Requires a full tube of blood.


White Top EDTA (PPT) Tube, 13 x 100 mm, 5 mL. Contains 9 mg of dried K2EDTA and gel separator. Invert 8 – 10 times to mix. This tube is used for HIV-1 and HCV viral quantitation.


Tan Top Tube - 13 x 75mm, 3 mL. Contains 5.4 mg of powdered K2EDTA for blood lead and heavy metal screen. Invert 8 – 10 times to mix. Requires a full tube of blood.


Lavender Top Tube, 13 x 75 mm, 4 mL. Contains 7.2 mg K2EDTA to chelate calcium, preventing coagulation. Invert 8 – 10 times to mix. Minimum required volumes: CBC + PLT - 1 mL, ESR - 2 mL, hemoglobin electrophoresis, Hgb A2, and F - 5 mL, G6PD, quantitative - 1 mL, and renin - 5 mL. Hgb H prep, Heinz bodies, fetal hemoglobin stain - 1 mL, CD4/CD8 - 1 mL.


Gray Top Tube, 13 x 75 mm, 4 mL. Contains 10 mg sodium fluoride to inhibit glucose metabolism; 8 mg potassium oxalate to chelate calcium and prevent coagulation. Invert 8 – 10 to mix. Minimum required volume: Glucose determination 2 mL. There is no preservative to inhibit glucose degradation in green or gold top tubes.


C. Capillary Blood Collection Tubes. Capillary Blood Collection Tubes have non-sterile interiors and contain the following:

Lavender Tube (250-500 mcL) - Contains EDTA Na2 (Disodium EDTA) sufficient to anticoagulate 500 mcl of capillary blood. Mix by inverting 10 times. This tube is used for hematology tests and blood lead on pediatric and newborn patients.

Amber Tube (500 mcL) - This tube is used to collect and separate capillary blood samples for maximum usable serum yield. This system is composed of a plastic tube with inert barrier material and a yellow lid. Mix by inverting 10 times. This tube is used for bilirubin and drug levels on pediatric and newborn patients.

Green Tube (200-400 mcL) - Contains lithium heparin. Mix by inverting 10 times. This tube is used for most STAT chemistry tests.



  1. URINE: Special Instructions For Collection of Urine Specimens; timed collection, preservatives


The Clinical Laboratory furnishes containers for timed (ex.: 5, 12, 24 hr) urine specimen collection, with preservative as necessary, upon request. Call Laboratory Support Services (Mon. - Fri.) 206-8199 to request a container. Containers may be stocked in the Main Lab as well; call 206-8590 for availability.


Refrigeration is the most important aspect of specimen preservation. All timed urine collections must be refrigerated during and after collection. Each container will be labeled with the preservative used, and instructions for collection of the urine specimen will accompany the container. Lab Support Services will supply properly cleansed and prepared bottles for other 24-hr urine tests or special tests not listed below. Call Specimen Collection and Management division at 206-8590 for further information.


Routine Urinalysis testing cannot be performed on timed urine specimens.


URINE COLLECTION LIST

(Special tests that are not included in the Alphabetical List of Tests. When prompted, click on link for more information regarding patient preparation and specimen collecion. Please contact the Inquiry Desk, Specimen Collection and Management, at 206-8590 for further assistance.)

** All urines are to be refrigerated during collection. **

Aldosterone

24 hr collection, no preservative

Amino Acid Screen (click for additional patient preparation instructions)

random, no preservative; first morning urine preferred

Aminolevulinic Acid (ALA) (click for additional patient preparation instructions)

24 hr or random collection, protect from light

Catecholamines (click for additional patient preparation instructions)

24 hr collection; random acceptable

Citrate

24 hr or random collection, no preservative preferred. Boric acid acceptable.

Copper (click for additional patient preparation instructions)

24 hr or random collection, no preservative, use plastic container

Cortisol (Free)

24 hr or random collection, no preservative

Creatinine

24 hr collection, no preservative

Cystine

24 hr or other timed collection, no preservative

Epinephrine

see Catecholamines


Heavy Metal Screen (Arsenic, Lead, Mercury) (click for additional patient preparation instructions)

24 hr or random collection , use plastic container, no preservative

Homovanillic Acid (click for additional patient preparation instructions)

24 hr or random collection, no preservative

17-Hydroxycorticosteroids

24 hr collection; 10 gm boric acid at start of collection, or no preservative OK. Random, no preservative OK if frozen within 15 mins of collection.

5-HIAA (click for additional patient preparation instructions)

24 hr collection or random; no preservative

Inborn Errors of Metabolism (Metabolic error screen)

10 mL (3 mL minimum), no preservative

17-Ketosteroids

24 hr collection, no preservative

Lead

See Heavy Metal Screen

Lysozyme

random collection, no preservative

Magnesium

24 hr collection, 10 mL 6N HCl at start of collection

Metanephrines (click for additional patient preparation instructions)

24 hr collection, no preservative. Random acceptable.

Norepinephrine

see Catecholamines

Organic Acids Screen

random collection only, freeze immediately

9 mL (3 mL minimum), no preservatives

Oxalate (click for additional patient preparation instructions)

24 hr collection, 10 mL 6N HCl at start of collection

Porphobilinogen

24 hr collection in dark bottle, protect from light, refrigerate. Random acceptable.

Porphyrin

24 hr collection in dark bottle, protect from light, refrigerate. Random acceptable.

Porter Silber

see 17-Hydroxycorticosteroids

Supersaturation Profile (Urinary Stone Risk Analysis)

24 hr collection only, no preservative.

Vanillylmandelic Acid (VMA) (click for additional patient preparation instructions)

24 hr collection, no preservative. Random acceptable.


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