Randomized trial interpreting sputum quality in a clinical laboratory.

The role for laboratory interpretation of microbiologic results remains controversial, and many laboratories leave the interpretation of culture results entirely to physicians. We examined the effects of furnishing a laboratory interpretation of sputum quality on physician decision making. Quality of sputum was determined on Gram-stained smears by using a modification of the criteria of Bartlett (R. C. Bartlett, Medical Microbiology: Quality, Cost, and Clinical Relevance, p. 24-31, 1974). A total of 301 poor-quality specimens were randomized either to receive written interpretation of Gram stain results or to a control group for which Gram stain results were reported without interpretation. Physicians were more likely to follow up a poor-quality specimen with a second specimen if they had been furnished an interpretation of the results from the original Gram stain (22 versus 12%; P = 0.025). We conclude that laboratory-based interpretation of microbiologic results can improve physician decision making.