Acceptability and cost savings of selective sputum microbiology in a community teaching hospital

Our experience in introducing selective sputum microbiology into a clinical laboratory was recorded prospectively and analyzed. Based on low-power microscopy with determination of ratios of polymorphonuclear to squamous cells, 32% of specimens were discarded as unfit for culture. Speedy processing and prompt telephone calls afforded opportunities to replace these with better specimens, but only 29% of rejected specimens were resubmitted. Interpretive readings of smears for microorganisms yielded meaningful yielded meaningful information to clinicians and correctly predicted culture results in 73.8% of acceptable specimens. Technological time was similar to that required to process the same number of specimens in the usual way, but rejection of unsatisfactory specimens led to a 22% saving in supplies. Clinicians readily accepted the new system. Where nurses are responsible for specimen collection, they must be informed of the rationale for selective culture and the unreliability of gross visual inspection in evaluating sputum.