Standards of TB Care in India related to Diagnosis of TB

Standards of Tuberculosis (TB) Care in India - Pillar 1

A total of six standards related to tuberculosis detection have been mentioned in the standard of TB Care in India guidelines. Each of these standards is described below:

Standard 1: Testing and Screening for Pulmonary TB

• Any person (adult and child) presenting with signs and symptoms suggestive of pulmonary TB should be evaluated for TB.
• Key and vulnerable populations should be regularly screened for signs and symptoms of TB.

Standard 2: Diagnostic Technology  

• All presumptive pulmonary TB patients capable of producing sputum should undergo a quality-assured sputum test for rapid diagnosis of TB. For optimal results, two sputum samples should be tested. One of these should be an early morning sample.
• Wherever available, chest X-rays should be included in the diagnostic algorithms to increase the sensitivity of TB detection.
• Serological tests like Interferon Gamma Release Assay (IGRA) and Tuberculin Skin Test (TST) are not recommended for the diagnosis of active TB.
• Owing to its higher sensitivity and lower limit of detection, Cartridge-based Nucleic Acid Amplification Test (CBNAAT) should be the preferred first diagnostic test in children and People Living with HIV (PLHIV).

Standard 3: Testing for Extra-pulmonary TB

• For all patients (adults, adolescents and children) with presumptive extra-pulmonary TB, appropriate specimens from the presumed sites of involvement must be obtained for microscopy/ culture and Drug Sensitivity Testing (DST)/ CBNAAT/ molecular test/ histopathological examination.

Standard 4: Diagnosis of HIV Co-infection in TB Patients and Drug-resistant TB (DR-TB)

• As a part of bidirectional testing, all diagnosed TB patients should be offered HIV counselling and testing.
• All presumptive DR-TB patients, non-responders, and other key and vulnerable population should be tested for drug resistance with the available technology, preferably with a rapid molecular Drug Resistance Testing (DRT) or solid/ liquid DST for at least rifampicin and if possible, for isoniazid too.
• On detection of resistance to rifampicin with or without isoniazid resistance, the patient must be offered second-line DST/ DRT using National TB Elimination Programme (NTEP) approved phenotypic or genotypic methods.
• This DST should be offered to all the patients before the start of the treatment.

Standard 5: Probable TB

• Presumptive TB patients in whom microbiological confirmation could not be established but have a strong clinical suspicion may be labelled as probable TB and should be treated.

Standard 6: Paediatric TB

• For children with presumptive intra-thoracic TB, microbiological confirmation should be sought through examination of respiratory specimens with quality assured diagnostic test, preferably CBNAAT, smear microscopy or culture.
• In case microbiological confirmation is not established, children with the presence of abnormalities consistent with TB on chest radiograph, contact history, or evidence of TB infection should be treated as probable TB.
• For children with presumptive extra-pulmonary TB, appropriate specimens from the presumed sites of involvement should be obtained for a rapid molecular test, microscopy, culture and DST, and histopathological examination.

Resources

• Standards for TB Care in India, World Health Organisation, 2014.

Assessment