Experience with a microscopic screening program for sputum specimens.

Microscopic examination of almost 2,000 sputum specimens was performed over a 3 1/2-month period. The specimens were categorized into 6 groups based on numbers of leukocytes (PMN's) and squamous epithelial cells (SEC's) observed at low magnification (X 100). Bacteriologic evaluation of specimens consisted of identification and antimicrobial susceptibility tests of potential pathogens when growth was equal or predominant to the growth of oropharyngeal flora. Specimens containing greater than 25 PMN's and less than 25 SEC's had potential pathogens identified in 51% of the samples. Specimen containing greater than 25 SEC's and any number of PMN's showed a rate on only 19%. Specimens containing less than 25 PMN's and SEC's had a rate of 13%. Since initiating the screening program in which sputum specimens containing greater than 25 SEC's were unacceptable for culture, the per cent of acceptable specimens received by the laboratory nearly doubled.