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microbial diseases laboratory

Test Order Mycobacteria Isolation from Specimen

Pre-Approval Required

Yes. Consult with Mycobacterial & Parasitic Diseases Reference Unit before submitting specimens. Specimens sent without prior approval may not be tested.

Supplemental Information or Form

Form LAB 402 

Performed on Specimens From

Human sources

Acceptable Sample/Specimen Type for Testing

Respiratory specimens (sputum, bronchial alveolar lavage, etc.), tissue or body fluid.  Swabs are suboptimal for culture and AFB Smear.

Minimum Volume Required

5 mL recommended; 1 mL minimum

Storage & Preservation of Sample/Specimen Prior to Shipping

Store specimen at 2°C to 8°C; specimens should be submitted as soon as possible after collection.  

Transport

Ship with cold packs.  Do not freeze.

Sample/Specimen Labeling

Testing subject to CLIA regulations require two patient identifiers on the specimen container and the test requisition. Patient’s name and collection date and time must be on specimen containers for samples processed for mycobacterial isolation and AFB smear. Additional acceptable identifiers include submitter’s accession number, patient ID, and date of birth.

Shipping Instructions which Include Specimen Handling Requirements

Ship as diagnostic specimen with cold packs. Do not freeze.  

Test Methodology

Digestion and decontamination, inoculation onto liquid and solid culture media, acid-fast microscopy using fluorescent auramine-rhodamine stain, phenotypic and molecular (MALDI-TOF and Sequencing) on AFB-positive cultures.

Turnaround Time

6 weeks for AFB negative cultures; up to 3 weeks if culture is positive for Mycobacterium tuberculosis complex and 4 weeks for mycobacteria other than M. tuberculosis complex. A preliminary report will be issued if culture becomes positive and AFB are observed.

Interferences & Limitations

The overgrowth of bacterial and/or fungal contaminants in positive cultures can prevent the isolation and identification of the acid-fast bacilli.

Additional Information

If M. tuberculosis complex is isolated from a new patient, drug susceptibility testing will be performed using culture and molecular methods (Pyrosequencing).

MDL Points of Contact

Mycobacterial & Parasitic Diseases Reference Unit
(510) 412-3924
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