The reliability of gastric smears by auramine-rhodamine staining technique for the diagnosis of tuberculosis.

From 1972 to 1974, all sputum specimens and gastric aspirate specimens submitted to the University of Michigan Laboratory for acid-fast smear and culture were studied. Specimens were paired for culture and smear results using the auramine-rhodamine staining technique. Of 1,893 patients, 75 patients without prior antituberculous therapy were found to have either a positive smear or a positive culture of either sputum or gastric material. The data analyzed by patient source revealed the following. (1) Staining sputum with auramine-rhodamine is a clinically reliable technique for detecting pulmonary tuberculosis. It demonstrates a sensitivity of 78 per cent and a relative fraction of false positive smears of only 11 per cent. (2) Staining gastric-aspirated material by the auramine-rhodamine technique is not a clinically reliable method as a routine procedure for the detection of pulmonary tuberculosis, because of a sensitivity of only 58.8 per cent and a relative fraction of false-positive smears of 33 per cent. (3) In the absence of sputum in suspected clinical granulomatous disease, quantified gastric smears may be helpful. In this study, when more than 6 organisms per high power field were found, the patient's sputum or gastric material yielded a pathogenic mycobacterium on culture.