In 2013, WHO issued updated TB case definitions and classifications

• A bacteriologically confirmed TB case is one from whom a biological specimen is positive by smear microscopy, culture or a WHO approved rapid diagnostic test (such as Xpert MTB/RIF).


• A clinically diagnosed TB case is one who does not fulfil the criteria for bacteriological confirmation but has been diagnosed with active TB based on other clinical evidence such as chest x-ray and where a clinician has decided to give the patient a full course of TB treatment.


• Clinically diagnosed cases subsequently found to be bacteriologically positive with Xpert MTB/RIF or culture (before or after starting treatment) should be reclassified as bacteriologically confirmed.