WHO endorsed TB tests; phenotypic tests consist of Microscopy (ZN and Fluorescence), liquid culture (MGIT 960, BD), and genotypic testing consist of CBNAAT (GeneXpert MTB/RIF) and Line probe assay (LPA). In the ‘Focus TB’ platform, these tests are made available at affordable prices to patients.
TECHNOLOGIES WE USE
Direct ZN microscopy of sputum smears is done to quickly detect the TB infection. Mycobacteria has a distinguished thick lipid cell wall that remains stained even after washing with acid-fast reagents. This a simple and inexpensive method for the quick detection of acid-fast bacilli.
Fluorescent microscopy is more sensitive than ZN microscopy for the detection of the TB bacterium.
Liquid and solid cultures are used as definitive diagnosis of MTBC and to distinguish it from other Mycobacterial species. DST technique is used to test for resistance of TB bacteria to certain drugs.
At Thyrocare, we are performing liquid culture by MGIT 960 and drug susceptibility testing for 13 drugs with critical concentrations recommended by WHO.
This is a rapid molecular diagnostic technique with high sensitivity for TB diagnosis in sputum and other body fluids. This test uses DNA amplification for detection of M. tuberculosis.
This is one of the latest techniques in the field of TB diagnostics. The need for fast and accurate results is ever increasing for TB diagnosis and it is also important to determine drug resistance; GeneXpert MTB/RIF comes as an ideal solution for high sensitivity and specificity. This technology helps in detecting simultaneously M. tuberculosis complex (MTBC) and rifampin resistance .
The GeneXpert MTB/RIF test is a cartridge based nucleic acid amplification assay (CB-NAAT) which uses real time-PCR for detection of an MTB-specific region of rpoB gene. It detects mutations associated with rifampicin resistance.
Multi-drug resistance TB poses a potential threat to TB control due to its treatment challenges. Line probe assay is a novel technology for rapid detection of anti-TB drug resistance, in first line and second line drugs. This assay involves extraction of M. tuberculosis DNA from clinical specimens and subjecting it to PCR for the amplification of the resistance determining regions of the gene using biotinylated primers. After amplification, the labelled PCR products are hybridized to specialized probes that are immobilized on a strip. The hybrids fixed on the strips are detected by colorimetric development, detecting the presence of MTBC and mutant genes for resistance.
Patients with Drug Resistance such as multidrug resistance (MDR) or extremely drug-resistant (XDR) TB show lower rates of treatment success. One of the main criteria to treating TB patients successfully is to administer the right treatment early. Whole-genome sequencing (WGS) is a technique that can be used to rapidly diagnose DR-TB by providing rapid, detailed and information for multiple gene regions across the whole TB genome. This approach overcomes many challenges associated with conventional phenotypic testing as well as the limitations of other less comprehensive molecular tests. The TGS is based on such technology. It is a WGS based test powered by the ΩTB® analytics by HaystackAnalytics Pvt. Ltd. that combines genome sequencing and analysis for a faster, more sensitive, more reliable, and cost-effective method of tuberculosis diagnosis.