Computer files and analyses of laboratory data from tuberculosis patients. II. Analyses of six years' data on sputum specimens.

Laboratory data on sputum specimens from patients with pulmonary mycobacterioses between 1968 and 1973 were analyzed. Specimens were cultured on Middlebrook 7H10 and/or 7H11 medium; blue light fluorescence microscopy was used to examine specimen smears. An admission series of 6 sputum specimens detected 94.7 per cent of all culture-positive patients. Only 62 per cent of patients who were culture positive in the admission series would have been detected by smear alone. Quantitative agreement of smear and culture results was seen only in the smear-numerous (more than 2 bacilli per high-power field), culture-numerous (more than 100 colonies per plate) category. Qualitative agreement of smear and culture was 71 per cent. A total of 123 smear-positive and culture-negative specimens, representing 9 per cent of the total number of positive smears, was found among 6,251 sputum specimens from 270 culture-positive ptients. At least one smear-positive and culture-negative specimen was obtained from 23 per cent of the patients evaluated. During this period, improved housekeeping measures and drying of culture plates reduced the culture contamination rate from 9.8 to less than 5 per cent.