Classification of TB on the basis of diagnosis

On the basis of diagnosis, Tuberculosis (TB) can be classified into 2 main types:

1. Microbiologically confirmed TB
2. Clinically diagnosed TB

Microbiologically Confirmed TB

• Microbiologically confirmed TB refers to a presumptive TB case from which a biological specimen is positive for acid-fast bacilli/ Mycobacterium tuberculosis on smear microscopy, culture, or on a rapid diagnostic molecular test (such as Cartridge-based Nucleic Acid Amplification Test (CBNAAT)/ Truenat).
• All such diagnosed cases should be notified at the source, regardless of whether TB treatment has started.

Clinically Diagnosed TB

• Clinically diagnosed TB refers to a presumptive TB case that is not microbiologically confirmed but has been diagnosed with active TB by a clinician who has decided to give the patient a full course of anti-TB treatment.
• This definition includes cases diagnosed on the basis of X-ray abnormalities or suggestive histology or extrapulmonary cases without laboratory confirmation.
• Clinically diagnosed cases subsequently found to be microbiologically positive (before or after starting treatment) should be reclassified as microbiologically confirmed.

Resources

• Training Modules (1-4) for Programme Managers and Medical Officers, 2020.
• Definitions and Reporting Framework for Tuberculosis, WHO, 2013.

Assessment