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Test Order

Mycobacterium tuberculosis Complex:
Drug Susceptibility Testing, Second Line

Pre-Approval Required

None

Supplemental Information or Form

Form LAB 444 (03/12) (MDL-N-25), EXAMINATION FOR MYCOBACTERIUM TUBERCULOSIS DRUG SUSCEPTIBILITY  

Performed on Specimens from

California local public health laboratories

Acceptable Sample/Specimen Type for Testing

Pure culture

Minimum Volume Required

None

Storage & Preservation of Specimen Prior to Shipping

Incubated at 35-37°C (or refrigerated)

Transport Medium

None

Specimen Labeling

Patient’s name, accession number, inoculation or subculture date 

Shipping Instructions which Include Specimen Handling Requirements

Ship as infectious substance.

Test Methodology

MGIT 960. Drugs tested are amikacin 1.5 µg/ml, moxifloxacin 0.25 µg/ml, capreomycin 3µg/ml, and ethionamide 5µg/ml.  If there is resistance to moxifloxacin at 0.25 μg/ml, this predicts resistance to levofloxacin as well.  When there is moxifloxacin resistance, a “mini-MIC” is performed, testing with moxifloxacin at 0.5, 1, 2, and 3 μg/ml.  If the initial testing shows ethionamide resistance, testing at 5 µg/ml and 10 µg/ml is performed.

Turnaround Time

7 to 14 days

Interferences & Limitations

Results unattainable because culture submitted is mixed with another mycobacteria (usually Mycobacterium avium complex) or another non-mycobacteria contaminant.

Additional Information

None

Mycobacteriology (drug susceptibilities) contact

(510) 412-3929

 
 
Last modified on: 10/8/2013 11:47 AM