25/08/2015
The GeneXpert : TB diagnosis in speed and accuracy
The GeneXpert is a small machine, about the size of a microwave oven It has been developed in the United States by a company called Cepheid and an organization called the Foundation for Innovative New Diagnostics (FIND),
it works on a molecular level (PCR) to identify *mycobacterium tuberculosis*
The machine looks for the DNA specific to the TB bacterium. If there are TB bacteria in the sample, the machine will detect their DNA and automatically multiply it.
The Gene Xpert can test for resistance to one of the most common TB drugs, rifampicin, so It is also called the Xpert MTB/RIF (for mycobacterium tuberculosis and rifampicin)
The sample for the test is commonly the sputum, but it can also work on other samples.
Advantage :
1) Can give very fast results at the same day( 2 hours)
2) Give good indicator that the patient might have multi-drug resistant (MDR)
“ TB MDR” is defined as resistance to isoniazid and rifampicin, with or without resistance to other first-line drugs (FLD).
3) More sensitive (up to 98%)
4) Improve the detection of TB (smear negative TB, TB-HIV, Extra pulmonary TB)
It is more expensive than the standard sputum-smear tests
It needs a thorough check at least once a year.
It also requires an uninterrupted supply of electricity.
The machine needs to be connected to a computer
Therefore, it is important that all clinics and hospitals where the Gene Xpert is used have proper and reliable infrastructure and security measures in place
