Sputum, MTB Complex, Rifampin Resistance, PCR

Important Note

Specimen Type: Sputum
Source: Expectorated, induced
Collection Container: Sterile container
Specimen Volume: 2 mL

1. Sputum previously processed in external laboratories is unacceptable.
2. AFB culture is also required when this test is ordered.  Sufficient volume must be received to perform both culture and MTB Complex PCR. If insufficient volume is received the MTB Complex PCR will be cancelled. 

Room temperature: Unacceptable
Refrigerated: 24 hours
Frozen: Unacceptable

Insufficient specimen volume received for both AFB culture and MTB Complex PCR

This test uses qualitative real-time polymerase chain reaction (PCR) for the detection of Mycobacterium tuberculosis complex DNA and rifampin-resistance associated mutations of the rpoB gene. The Xpert MTB/RIF assay is not indicated for use with sputum samples from patients being treated with antituberculosis drugs, either to determine bacteriologic cure or to monitor response to therapy. A positive test does not necessarily indicate the presence of viable organisms. A negative test does not exclude the possibility of isolating Mycobacterium tuberculosis (MTB) complex from the sample. Mycobacteria cultures are required to detect the presence of MTB complex that is below the limit of detection of this assay and also to detect mycobacteria other than tuberculosis complex. Due to the low prevalence of rifampin resistant TB in the United States, specimens with rifampin resistance detected will be sent for confirmatory testing.