According to RNTCP, case definition on sputum ex- amination includes
(C) Any of the two or both samples are positive out of two > Two sputum smear samples are examined. If any of the two samples or both the samples are positive, the diagnosis of smear positive TB is confirmed.# Diagnosis of pulmonary TB under RNTCP: Diagnosis is made primarily based on sputum smear examination. X-rays play a secondary role in the standard diagnostic algorithm for pulmonary tuberculosis> Sputum smear microscopy, using the Ziehl-Neelsen staining technique, is employed as the standard case-finding tool. Two sputum samples are collected over two days (as spot-morning/morning-spot) from chest symptomatics (patients with presenting with a history of cough for two weeks or more) to arrive at a diagnosis. In addition to the test's high specificity, the use of two samples ensures that the diagnostic procedure has a high (>99%) test sensitivity as well.> RNTCP pays more attention to the sputum-positive pulmonary tuberculosis patients (who are likely to spread the disease in the community) than people with other, non-pulmonary forms of the disease.
1 sample positive out of three samples
At least two samples positive out of two samples
Any of the tw o or both samples are positive out of Iwo
2 or 3 samples positive out of three
Miscellaneous