First line drugs are the least toxic and most effective drugs that are used in first line of therapy.
The first-line antituberculosis drugs that form the core of treatment regimens are
| Drugs |
Characteristics |
|---|---|
|
Rifampicin (R) |
Helps in early clearance of tuberculosis bacteria from the specimen |
|
Isoniazid (H) |
Educating patients on collection is essential to have good quality sputum. The healthcare worker (HCW)/ medical officer (MO) or the laboratory technician (LT) can educate patients on how to collect and dispense sputum.
The HCW/MO/LT provides a new sputum cup with the Laboratory Serial Number written on its side to the patient. They should explain that sputum should be collected in an open place or in a well-ventilated room; it should not be collected in closed rooms, toilets and ill-ventilated rooms
Active TB disease has 4 major symptoms (the 4 Symptom complex). Presence of any one of these symptoms without any other reason warrants evaluation for TB. These are:
Figure: Signs and Symptoms of TB
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:
Presumptive TB case refers to a patient who presents with symptoms or signs suggestive of TB disease (previously known as a TB suspect) and where further diagnostic workup including bacteriological investigation is required.
Presumptive TB can be categorized into
Presumptive Pulmonary TB (P TB) - Symptoms are directly related to lungs (Cough, hemoptysis)
Presumptive Extra Pulmonary TB (EP TB) - Symptoms/ signs are specific to an extra pulmonary site (example: Lymph node swelling)
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:
