TB MDR Screen Test: Purpose, Normal Range and Price

Key facts about the Tb Mdr Screen test
Also Known As	MDR-TB Molecular Screen, TB Drug Resistance LPA Test, Rifampicin and Isoniazid Resistance Test
Sample Type	Sputum (early morning), CSF, Pleural Fluid, Lymph Node Aspirate
Fasting Required	No (mouth rinse with plain water before sputum collection required)
Report Delivery	Within 24 hours
Age Group	All age groups
Gender	All
Test Type	Line Probe Assay (LPA) / Next-Generation Sequencing (NGS) / PCR-based Molecular Detection
Units	Qualitative (Detected / Not Detected, per drug class)

The TB MDR Screen test is a molecular diagnostic test that detects the presence of Mycobacterium tuberculosis and simultaneously identifies genetic mutations conferring resistance to the two most critical first-line anti-TB drugs, rifampicin and isoniazid. A strain resistant to both rifampicin and isoniazid meets the WHO definition of multidrug-resistant tuberculosis, commonly referred to as MDR-TB, which requires an entirely different, longer, more complex, and significantly more expensive treatment regimen than drug-sensitive TB. The test uses advanced molecular techniques including line probe assay or next-generation sequencing platforms to detect specific resistance-conferring mutations in the rpoB gene for rifampicin resistance and the katG and inhA genes for isoniazid resistance directly from clinical specimens. MDR-TB represents one of the most serious public health threats in global infectious disease, and India bears a disproportionately high burden, accounting for approximately 27 percent of the world's MDR-TB cases according to WHO estimates. The emergence of MDR-TB in India is driven by incomplete treatment courses, inadequate drug supply, poor treatment supervision, transmission of already-resistant strains, and the prescribing of subtherapeutic regimens in the private sector. Left undetected, MDR-TB patients treated with ineffective standard regimens continue to deteriorate clinically, accumulate further resistance mutations, and transmit drug-resistant strains in the community. Rapid identification of MDR-TB through molecular screening is therefore both a clinical imperative for the individual patient and a public health necessity for preventing further resistance amplification and community spread. The test is performed on a sputum specimen or other relevant clinical sample collected under appropriate conditions.

Doctors prescribe a TB MDR Screen test in the following situations: Investigating treatment failure in patients already receiving standard first-line anti-TB therapy who show no clinical or bacteriological improvement after two to three months of treatment, where molecular resistance screening identifies whether MDR-TB is the underlying reason for treatment failure and guides urgent regimen modification. Evaluating TB relapse in patients who have previously completed a full course of anti-TB treatment and present with recurrent symptoms and positive bacteriology, where prior drug exposure creates conditions favouring the selection and emergence of resistant mutants that standard retreatment regimens will fail to eliminate. Screening close contacts of confirmed MDR-TB index cases where household members and close contacts are at significantly elevated risk of having acquired a drug-resistant strain through prolonged exposure, and early molecular screening enables pre-emptive diagnosis and treatment before advanced disease develops. Diagnosing TB in patients with a history of prior incomplete or irregular anti-TB treatment where the risk of acquired drug resistance is substantially elevated and empirical use of standard first-line drugs without resistance testing risks further treatment failure and additional resistance accumulation. Assessing new TB patients from high MDR-TB prevalence settings, migrant populations, and individuals with HIV coinfection where baseline MDR-TB screening at the point of initial diagnosis is increasingly recommended to avoid inadvertent treatment with an inadequate regimen from the outset. Guiding individualised drug-resistant TB regimen construction in patients with confirmed or suspected MDR-TB where identification of specific resistance mutations beyond rifampicin and isoniazid informs which second-line drugs remain active and which should be avoided in the treatment regimen designed by a specialist DR-TB team.

The TB MDR Screen test detects Mycobacterium tuberculosis DNA and identifies mutations in resistance-associated genes for rifampicin and isoniazid, reporting results qualitatively. Some advanced platforms also provide semi-quantitative bacterial load information alongside resistance profiling. MTB Not Detected A not detected result indicates that Mycobacterium tuberculosis DNA was not identified in the specimen tested. This effectively rules out active TB in the tested sample, though a single negative result in a patient with strong clinical and radiological suspicion warrants repeat testing with a fresh specimen or alternative sample type before TB is conclusively excluded. MTB Detected, Rifampicin and Isoniazid Sensitive This result confirms active TB infection with sensitivity to both rifampicin and isoniazid, indicating that the strain does not meet the definition of MDR-TB. Standard first-line treatment under the National TB Elimination Programme is appropriate, and treatment should be initiated promptly with mandatory programme notification and contact tracing. MTB Detected, MDR Confirmed This result confirms the presence of Mycobacterium tuberculosis with resistance mutations to both rifampicin and isoniazid, meeting the WHO and NTEP definition of multidrug-resistant tuberculosis. This finding requires immediate referral to a designated DR-TB treatment centre, initiation of an MDR-TB regimen under specialist supervision, mandatory notification to the national TB programme, and systematic contact tracing of all close contacts.

The TB MDR Screen test is most commonly performed on an early morning sputum specimen, and optimal specimen quality is critical for accurate molecular results. Patients should collect a deep cough sputum specimen early in the morning before eating, drinking, or using any oral hygiene products, as early morning sputum has the highest bacterial concentration and yields the best diagnostic sensitivity for molecular testing. Before providing the sputum sample, rinse your mouth thoroughly with plain water only. Toothpaste, mouthwash, and antiseptic oral rinses contain agents that can inhibit the PCR reaction and reduce test sensitivity, and their use immediately before specimen collection should be strictly avoided. Collect the specimen in the sterile container provided by the laboratory, ensuring it contains genuine lower respiratory tract sputum rather than saliva. Inform your doctor if you are already receiving anti-TB medications at the time of testing, as prior antibiotic exposure can reduce bacterial load in specimens and may affect detection sensitivity. If the specimen is being collected from a non-sputum site such as CSF, pleural fluid, or lymph node aspirate, your treating physician will provide specific pre-procedure instructions. Prompt laboratory transport of collected specimens at 2 to 8 degrees Celsius preserves nucleic acid integrity and ensures reliable molecular results.

If you are booking through the SecondMedic platform the TB MDR Screen test price starts at approximately Rs. 3385. The exact price will be confirmed at the time of booking through SecondMedic. If your doctor has prescribed multiple tests alongside TB MDR Screen, SecondMedic health packages include MDR Screen as part of a broader comprehensive drug-resistant TB panel at a significantly lower combined price.

SecondMedic offers convenient home sample collection for the TB MDR Screen test across India, making it easy to get tested without visiting a diagnostic centre. Home collection is available free of charge for orders above Rs. 300. A trained professional will visit your preferred address between 7 AM and 10 PM, seven days a week, including Sundays and public holidays. Your sample is processed at NABL-accredited partner laboratories, and your report is delivered within 24 hours directly to your WhatsApp and email.