Gene X-pert Test: MTB Detection and Resistance
The Gene X-pert test, specifically the Xpert MTB/RIF assay, is a rapid molecular test used for diagnosing Tuberculosis (TB) caused by Mycobacterium tuberculosis (MTB).
Key Advantages of Gene X-pert MTB/RIF
- Simultaneous Detection: It detects the presence of MTB DNA.
- Resistance Detection: Critically, it simultaneously detects resistance to Rifampicin, a key first-line anti-TB drug. This is achieved by identifying mutations in the rpoB gene, which are strongly correlated with Rifampicin resistance.
Analysis of Options
- INH resistance: The standard Xpert MTB/RIF assay does not directly detect Isoniazid (INH) resistance.
- Rifampicin resistance: This is the primary additional resistance marker detected by the Xpert MTB/RIF assay alongside MTB detection.
- Multi drug resistance: While Rifampicin resistance is a component of Multi-Drug Resistance (MDR-TB), the Xpert MTB/RIF assay alone doesn't confirm MDR-TB as it doesn't test for INH resistance.
- Ethambutol resistance: The Xpert MTB/RIF assay does not detect Ethambutol resistance.
Therefore, the additional advantage of the Gene X-pert test (Xpert MTB/RIF) is the detection of Rifampicin resistance.
Important Questions from Tuberculosis
Which of the following investigations may be used for the diagnosis of pulmonary tuberculosis?
1. Nucleic acid amplification
2. Culture in Middlebrook medium
3. Light emitting diode fluorescent microscopy with auramine staining
4. Peripheral blood smear
Select the correct answer using the code given below:
- Recommended first time drug for initial treatment of tuberculosis include all EXCEPT:
The most frequent adverse reaction of significance among people treated for drug-susceptible tuberculosis is:
All adult patients in whom anti-tubercular treatment is being started should undergo baseline assessment of:
- The extrapulmonary sites most commonly involved in tuberculosis are all EXCEPT:
