Submit 5-15 mL sputum specimen in a sterile leak-proof container refrigerated at 2-8 °C. Place each individual specimen in a sealed bag.

Source of specimen indicated on requisition is required. MTD testing must be accompanied by an Acid Fast Bacilli Culture order (AFBCU). Routinely, only one specimen per patient will be tested (If for isolation release protocol, 2 specimens may be tested, but must be at least 8 hours apart.) Positive AFB smears on first time AFB positive patients will be automatically reflexed for testing.

The test is specific for, but does not differentiate among, members of the M. tuberculosis complex.

Method change for Amplified Mycobacterium tuberculosis direct test

Effective July 25, 2011, the laboratory will replace the GenProbe Amplified Mycobacterium tuberculosis direct test with the Cepheid GeneXpert MTB Assay to detect Mycobacterium tuberculosis (MTB) complex directly from sputum specimens. The test utilizes quantitative real time PCR technology that can be used on either acid fast bacilli (AFB) smear positive specimens or AFB smear negative specimens. Based on CDC recommendations, the test is appropriate for patients showing symptoms of active pulmonary tuberculosis and for whom the test result would alter case management or TB control activities. A specimen with a first time AFB positive smear on a suspect tuberculosis patient will also be automatically reflexed for Mycobacterium TB Amplified Direct Testing. Only one specimen per patient will be tested.

Quantitative Real Time PCR

Negative

A negative result does not exclude M. tuberculosis infection.