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If you have additional questions regarding this test, please call: 415-353-1667
AFB Culture, Non-Respiratory (New test)
|Approval req'd?||Yes for:
- CSF unless submitted by neurology or neurosurgery services
- Joint fluid
- Abdominal drainage
- Urine unless from urology patient
- < 2 ml fluid submitted
Contact Microbiology at 353-1268
|In House Availability||Daily, day shift|
Note: the diagnostic yield for joint and body fluid samples is low. If mycobacterial infection is suspected from these sites, tissue is the preferred specimen.
|Amount to Collect||
|Sample type||Bone marrow, CSF, body fluids, urine, unfixed tissue, FNA|
|UCSF Rejection Criteria||Samples submitted on swabs or in formalin|
|Processing notes||Bone marrow: Store at room temperature until processed. Process specimen immediately upon receipt in microbiology
Gastric lavage: If processing will be delayed by more than 5 hours, give specimen to CLS to neutralize.
Tissue: Grind a piece of tissue using NPC 67 Neutralizing buffer and transfer to blue top centrifuge tube.
CSF: If approved, enter volume used for culture in SDES and AFBVOL in SREQ. (The yield of CSF AFB culture increases with greater specimen volume. Recommended volumes are > 6 ml for pediatrics and 15-20 ml for adults.)
Note: If CSF AFB smear is approved, alert AFB processor and do NOT credit AFB smear.
|Normal range||No AFB isolated|
|Critical value||First positive acid fast smear. Positive culture (if no or negative smear). First M. tuberculosis isolate. Positive CSF culture. Repeat call only for positive sample from different site or > 2 months since initial call.|
|Synonyms||TB culture; AFB culture; tuberculosis; atypical mycobacteria; MAC; mycobacteriaum avium intercellulare complex; MAI|
|Turn around times||Up to 7 weeks|
|Additional information||Separate charges will be billed for AFB smear and AFB culture. Additional charges will be billed for decontamination of samples from non-sterile sites
Smears will be performed on appropriate samples. Samples are run w/o smear when a positive result would not be interpretable because of relatively frequent contamination with nonpathogenic mycobacteria which cannot be reliably differentiated on smear (e.g., in urine or gastric fluid), or for blood, bone marrow, CSF or pleural fluid where the yield of routine testing is low.
Tuberculous arthritis, meningitis, and urinary infection are extremely uncommon diagnoses at this hospital, and cultures should only be requested if the cellular response is highly suggestive of tuberculosis, if there is a history of tuberculosis or close contact with a case, if there is a positive tuberculin test, or if granulomas are found in a biopsy specimen.
Bone marrow is the preferred specimen in non-AIDS patients with disseminated disease, in whom the yield from blood is extremely low.
|Last Updated||3/3/2016 12:43:59 PM|