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The Senior TB Laboratory Supervisor (STLS) is the person responsible for monitoring the day-to-day activities of all the microscopy centres and nucleic acid amplification test (NAAT) sites and is thus essential to the success of the National TB Elimination Programme (NTEP). They also ensure the quality of TB diagnostic services.

Roles of STLS at the DMC

For laboratory diagnosis of TB, different biological specimens are used.

Pulmonary TB: Sputum sample is used. Sputum is a thick fluid produced in the lungs and in the adjacent airways. Normally, a spot sample and a fresh morning sample is preferred for the bacteriological examination of sputum.

Extra Pulmonary TB:

Resources:

The National Tuberculosis (TB) Elimination Program (NTEP) has a network of Nucleic Acid Amplification Tests (NAAT) laboratories coupled with Designated Microscopy Centers (DMCs) to form the backbone of the diagnostic component of TB services.

Nucleic Acid Amplification Tests (NAAT) laboratories includes Cartridge-based NAAT (CBNAAT) and TrueNat tests. These tests detect tuberculosis as well as rifampicin resistance and are more sensitive than smear microscopy.

NTEP laboratory network is comprising of National Reference Laboratories (NRLs), state level Intermediate reference laboratories (IRLs), Culture & Drug Susceptibility Testing (C & DST) laboratories and peripheral level laboratories. Peripheral level laboratories consist of  designated microscopy centres (DMCs) and NAAT labs.

NTEP has a quality assured laboratory network for bacteriological examination of sputum in a 3-tiered system.

Culture Drug Susceptibility Testing (CDST) is a growth-based phenotypic method used to check the susceptibility of Mycobacterium tuberculosis strains to various first and second line anti-TB drugs. Mycobacterial resistance to a particular drug is identified if there is growth observed in culture in presence of that drug.

Culturing TB Bacilli is well known and historic method for detection/ confirmation of Tuberculosis. It is a highly sensitive and specific phenotypic test; it can detect even a few viable bacilli in the sample (Upto 10 Colony Forming Units- CFUs). TB bacilli multiply in the culture and form colonies of TB bacilli which can are easily be identified.

Based on the growth media used Culture is divided in to two types, Solid and Liquid Culture methods. Types Culture:

As per the Integrated Drug Resistant Tuberculosis (DR-TB) Diagnostic Algorithm:

Second-line Line Probe Assay (SL-LPA) is a LPA to detect resistance to the second-line anti-TB drugs. This test is recommended for identifying TB patients with Multidrug-resistance (MDR) or rifampicin-resistance and those who can be placed on the shorter MDR-TB regimen.

The SL-LPA produces results in just 24-48 hours.

First Line (FL) LPA

• Performed using GenoType MTBDR plus ver 2.0 kit
• GenoType MTBDR plus (Figure) identifies:
  • Mutations in the Rif-resistance Determining Region (RRDR) of rpoB gene (from codon 505 to 533) to detect Rifampicin resistance
  • Mutations in the inhA promoter (from -16 to -8 nucleotides upstream) and the katG (codon 315) regions to identify Isoniazid resistance.