Two research studies in this week's PLoS Medicine suggest that a new automated DNA test for tuberculosis (Xpert MTB/RIF), which can detect TB within 2 hours and has been endorsed by the World Health Organization.
This can significantly increase TB detection rate compared to other tests, particularly in HIV positive patients who have a high risk of being infected with TB, including multi-drug resistant TB.
Image via WikipediaAccording to the WHO Global Tuberculosis Control Report 2009, there may be more than 500,000 cases of MDR-TB (Multi-drug resistant TB) worldwide. Current testing for drug resistance can take more than 4 weeks, leading to higher mortality and the further spread of MDR strains.
Other modalities of diagnosis of TB, such as microscopy that requires expertise; and culture diagnosis takes time in days. Some blood test kits are also quite ineffective and WHO has recently advised not to use the tests for diagnosis of TB.
The Xpert MTB/RIF is a cartridge-based, automated diagnostic test that can identify Mycobacterium tuberculosis (MTB) and resistance to rifampicin (RIF).
It was co-developed by Cepheid, Inc. and Foundation for Innovative New Diagnostics, with additional financial support from the US National Institutes of Health (NIH) and technical support from the University of Medicine and Dentistry of New Jersey (UMDNJ).
The Xpert MTB/RIF assay uses 3 specific primers and 5 unique molecular probes to ensure a high degree of specificity.
Assay targets the rpoB gene, which is critical for identifying mutations associated with rifampicin resistance.
No cross reactions were observed with many other bacterial species tested, including a comprehensive panel of Mycobacteria.
This test is simple to use and quick information can be gained; but requires investment.
This can significantly increase TB detection rate compared to other tests, particularly in HIV positive patients who have a high risk of being infected with TB, including multi-drug resistant TB.
Image via WikipediaAccording to the WHO Global Tuberculosis Control Report 2009, there may be more than 500,000 cases of MDR-TB (Multi-drug resistant TB) worldwide. Current testing for drug resistance can take more than 4 weeks, leading to higher mortality and the further spread of MDR strains.Other modalities of diagnosis of TB, such as microscopy that requires expertise; and culture diagnosis takes time in days. Some blood test kits are also quite ineffective and WHO has recently advised not to use the tests for diagnosis of TB.
The Xpert MTB/RIF is a cartridge-based, automated diagnostic test that can identify Mycobacterium tuberculosis (MTB) and resistance to rifampicin (RIF).
It was co-developed by Cepheid, Inc. and Foundation for Innovative New Diagnostics, with additional financial support from the US National Institutes of Health (NIH) and technical support from the University of Medicine and Dentistry of New Jersey (UMDNJ).
The Xpert MTB/RIF assay uses 3 specific primers and 5 unique molecular probes to ensure a high degree of specificity.
Assay targets the rpoB gene, which is critical for identifying mutations associated with rifampicin resistance.
No cross reactions were observed with many other bacterial species tested, including a comprehensive panel of Mycobacteria.
This test is simple to use and quick information can be gained; but requires investment.
