The Gene Xpert is a new test for tuberculosis.
The test simultaneously detects Mycobacterium tuberculosis complex (MTBC) and resistance to rifampicin (RIF) in less than 2 hours
In comparison, standard cultures can take 2 to 6 weeks for MTBC to grow and conventional drug resistance tests can add 3 more week
How Does the Assay Work?
It's actually assay is a nucleic acid amplification (NAA) test that uses a disposable cartridge with the GeneXpert Instrument System.
A sputum sample is collected from the patient with suspected TB.
The sputum is mixed with the reagent that is provided with the assay, .....and a cartridge containing this mixture is placed in the GeneXpert machine.
All processing from this point on is fully automated.
Importance
The test can detect if a TB bacterium has developed resistance to drugs.
In simple way .... actually The DNA of the TB bacterium is, in a way, like a long string of different colours. ....
If one or more of the colours change that is (if there is a mutation in the DNA), .....
then the bacterium can become resistant to certain TB drugs.
Now The Gene Xpert can test for resistance to one of the most common TB drugs, called rifampicin.
This means that it can tell us two things: first, whether or not a person has TB, and second, whether or not the TB that the person has can be treated with rifampicin.