Supplemental Information or Form
Form LAB 444 (03/12) (MDL-N-25), EXAMINATION FOR MYCOBACTERIA TUBERCULOSIS DRUG SUSCEPTIBILITY
Performed on Specimens from
Patients suspected of having drug-resistant tuberculosis, patients who are especially susceptible to treatment failure, cultures of M. tb complex mixed with non-TB mycobacteria or other bacteria.
Acceptable Sample/ Specimen Type for Testing
Sediment or culture. At least 0.5 ml of a sample which is acid-fast smear positive is requested.
Minimum Volume Required
0.5 ml for sediment
Storage & Preservation of Specimen Prior to Shipping
If sediment, refrigerate. If culture, incubate at 35-37°C.
Patient’s name, accession number
Shipping Instructions which Include Specimen Handling Requirements
Ship cultures of M. tb complex as infectious substances. Sediments may be shipped as diagnostic specimens with a cold pack.
Pyrosequencing (PSQ) to identify mutations associated with drug resistance in the following genes: rpoB for rifampin, katG, inhA promoter, and ahpC for isoniazid, gyrA for fluoroquinolones, and rrs for injectable drugs such as amikacin, capreomycin, or kanamycin. For more information on pyrosequencing, see the bulletin “Pyrosequencing (PSQ) for XDR TB Screening” (see Submission Instruction and Forms page).
1 to 3 days
Interferences & Limitations
There must be a satisfactory number of TB bacilli to yield an acceptable result. Specimens with at least 0.5 ml and an acid-fast positive smear 1+ or greater will generally generate an acceptable result. Sometimes inhibitory substances in the specimen may prevent successful DNA amplification and pyrosequencing.
MDL Points of Contact
Mycobacterial Diseases Section (drug susceptibilities) (510) 412-3929Email: firstname.lastname@example.org
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