The Xpert<unk> /RIF detects DNA sequences specific for Mycobacterium tuberculosis and<unk> ampicin resistance by polymerase chain reaction. It is based on the Cepheid<unk>  system, a rapid, simple-to-use nucleic acid amplification test (NAAT). The Xpert®<unk> /RIF purifies and concentrates Mycobacterium tuberculosis bacilli from sputum samples, isolates genomic material from the captured bacteria by sonication and subsequently amplifies the genomic DNA by PCR. The process identifies most of the clinically relevant<unk> ampicin resistance inducing mutations in the RNA polymerase beta (rpoB) gene in the Mycobacterium tuberculosis genome in a real time format using fluorescent probes called molecular beacons. Results are obtained from unprocessed sputum samples in 90 minutes, with minimal biohazard and very little technical training required to operate. This test was developed as an on-demand near patient technology which could be performed even in a doctor's office if necessary. A review to assess the diagnostic accuracy of Xpert TB found that when used as an initial test to replace smear microscopy it had pooled sensitivity of 89% and specificity of 99% . However, when Xpert TB was used as an add-on for cases of negative smear microscopy the sensitivity was only 67% and specificity 99%. In a clinical study conducted the sensitivity of the<unk> /RIF test on just 1 sputum sample was 92.2% for culture-positive TB; 98.2% for smear+ and culture-positive cases; and 72.5% for smear-negative, culture-positive cases, with a specificity of 99.2%. Sensitivity and higher specificity were slightly higher when 3 samples were tested.
GeneXpert MTB/RIF
T-SPOT.TB
Throat culture
Viral culture
Mantoux test
Microscopic Observation Drug Susceptibility assay
Sputum culture
Malaria culture