Final answer:
The GeneXpert MTB/RIF is an automated molecular test that uses PCR technologies for the rapid diagnosis of TB and detection of rifampicin resistance. It employs a genus-specific 16S rRNA PCR, species-specific IS6110 PCR, and other PCR methods, providing quick and sensitive TB diagnosis.
Step-by-step explanation:
The GeneXpert MTB/RIF is a molecular test for the diagnosis of tuberculosis (TB) and its resistance to rifampicin, an important first-line drug for TB treatment. The test is a fully automated nucleic acid amplification test (NAAT), which makes use of real-time polymerase chain reaction (PCR) to amplify and detect the DNA of Mycobacterium tuberculosis complex (MTBC) in clinical samples. Additionally, this test identifies the presence of the rifampicin resistance-mediating gene, rpoB, in less than two hours. The GeneXpert system is based on several key technologies including genus-specific 16S rRNA PCR and species-specific IS6110 PCR tests, which are nearly equivalent in quality to other PCR tests such as the Roche Amplicor MTB PCR test and the Amplified Mycobacterium tuberculosis Direct Detection test (AMDT). Furthermore, RNA extraction and reverse transcriptase PCR are utilized to detect mycobacterial RNA from infected samples, providing a highly sensitive method for TB diagnosis.