Genotyping for Mycobacterium (Line Probe Assay)

This is a molecular diagnostic test used to detect Mycobacterium species, particularly Mycobacterium tuberculosis, and identify genetic mutations associated with drug resistance.

This test uses advanced DNA-based techniques to rapidly detect tuberculosis (TB) and determine resistance to key anti-tubercular drugs such as rifampicin and isoniazid. Compared to conventional culture methods, the line probe assay provides faster results, enabling early diagnosis and appropriate treatment planning.

The purpose of this test is to:

• Detect Mycobacterium tuberculosis infection
• Identify genetic mutations linked to drug resistance
• Diagnose multidrug-resistant tuberculosis (MDR-TB)
• Enable early and accurate TB diagnosis
• Guide appropriate anti-tubercular treatment

GENOTYPING FOR MYCOBACTERIUM (LINE PROBE ASSAY) Test

The Genotyping for Mycobacterium – Line Probe Assay (LPA) is a molecular test used to identify Mycobacterium tuberculosis complex (MTBC) and detect specific genetic mutations associated with resistance to anti-tuberculosis medicines. It uses DNA amplification followed by reverse hybridization with probes designed to identify the organism and important resistance-associated mutations.

Depending on the LPA used, the test can detect mutations associated with resistance to important TB medicines. First-line LPAs commonly evaluate resistance to rifampicin and isoniazid by examining regions such as rpoB, katG, and the inhA promoter. Second-line LPAs can assess mutations associated with resistance to fluoroquinolones and certain second-line injectable drugs.

Because genetic testing can identify resistance-associated mutations much faster than conventional culture-based drug susceptibility testing, LPA can help healthcare professionals make timely decisions about appropriate TB treatment. However, results should be interpreted along with microbiological, clinical, and other drug-susceptibility findings.

GENOTYPING FOR MYCOBACTERIUM (LINE PROBE ASSAY) Test is Recommended for Individuals:

• Individuals with suspected or confirmed tuberculosis
• Patients with bacteriologically confirmed pulmonary TB requiring rapid resistance assessment
• Individuals suspected of having drug-resistant TB
• Patients with suspected rifampicin or isoniazid resistance
• Individuals with previously treated TB or a history suggesting increased risk of drug resistance
• Patients with confirmed rifampicin-resistant or multidrug-resistant TB who require evaluation for additional resistance
• Individuals whose healthcare provider needs rapid information about TB drug resistance
• Patients undergoing further investigation following an abnormal or positive TB molecular test

FAQs

1. What does a Mycobacterium Line Probe Assay detect?
Depending on the assay, it can identify Mycobacterium tuberculosis complex and detect specific genetic mutations associated with resistance to selected anti-TB medicines.

2. Which drug resistance can a Line Probe Assay detect?
First-line LPAs can detect mutations associated with rifampicin and isoniazid resistance. Second-line LPAs can detect mutations associated with resistance to fluoroquinolones and certain second-line injectable drugs. The exact drugs covered depend on the particular assay used.

3. Is Line Probe Assay the same as a TB culture test?
No. LPA is a molecular genetic test that detects TB DNA and resistance-associated mutations, whereas culture involves growing the organism and can be used for phenotypic drug susceptibility testing. LPA provides rapid genetic information, but additional testing may be required when clinically appropriate.