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Test Code MTBRIF Mycobacterium tuberculosis complex PCR with Rifampin Resistance gene detection

Important Note

Sputum is the only FDA acceptable specimen type

Infectious

Performing Laboratory

Bronson Laboratory-Microbiology

Reference Values

Not Detected

Specimen Transport Temperature

Room Temperature: Up to 72 hours

Refrigerated: Up to 7 days

Specimen Requirements & Patient Preparation

Sputum

Methodology

Real Time PCR

Day(s) Test Set Up

Monday through Sunday

Test Classification and CPT Coding

CPT Code(s) 87556 and 87798

 

Clinical Utility

The Xpert MTB/RIF Assay is an automated in vitro diagnostic test using nested real-time PCR for the qualitative detection of MTB-complex and RIF resistance. The primers in this test amplify a portion of the rpoB gene containing the 81 base pair core region. The probes are designed to differentiate between the conserved wild-type sequence and mutations in the core region that are associated with RIF resistance

The Xpert MTB/RIF Assay must always be used in conjunction with mycobacterial culture to address the risk of false negative results and to recover organisms when MTB-complex is present for further characterization and drug susceptibility testing.

Assay result of MTB Not Detected on two consecutive samples taken at least 8 hours apart is highly predictive of the absence of M. tuberculosis complex bacilli and can be used as an aid in the decision of wheather continued airborne infection isoloation (AII) is warranted in patients with suspected pulmonary  tuberculosis.