To compare the accuracy of infection control practitioners' (ICPs') classifications of operative site infection in Florida Consortium for Infection Control (FCIC) hospitals, in two time periods, 1990 to 1991 and 1991 to 1992, and to estimate the effect of duration of surveillance experience on that accuracy.

Medical record reviewers examined records of all patients classified by an ICP as infected, to distinguish false-positives from true infections based on evidence of standard infection criteria and the ICP's contemporaneous clinical observations. Reviewers also examined a random sample of 100 records from patients classified as noninfected for evidence of undetected infections (false-negatives). These observations permitted estimates of the sensitivity and specificity of each ICP's classification of infection status.

Fourteen FCIC communit:y hospitals at which performance of 16 ICPs was monitored.

There was a strong linear trend relating increasing sensitivity to numbers of years of ICP surveillance experience (P<.001). For ICPs with <4 years of experience, satisfactory sensitivity (≥80%) was reached in only one of 10 ICP-years of observation. For ICPs with ≥4 years' experience, satisfactory sensitivity was achieved for 14 of 18 person-years (P=.001). Estimated specificity was 97% to 100% for all ICP-years observed.

ICPs with <4 years of surveillance experience in FCIC community hospitals rarely achieved a satisfactory sensitivity estimate, whereas ICPs with≥4 years' experience generally did. Monitoring ICP surveillance accuracy through retrospective medical record audits offers an objective approach to evaluating ICP performance and to interpreting infection rates at different hospitals.

To investigate an apparent excess of operative site infections (OSI) reported according to doctor's diagnosis (presumptive OSI) by applying objective criteria for classification (documented OSI). To examine potential consequences of habitual overdiagnosis of OSI.

A case-control design was used to examine the clinical course of 18 case patients (12 presumptive OSI, six documented OSI) and 18 matched controls. Comparisons also were made between presumptive and documented OSI patients.

A nonteaching community hospital.

Thirty-six patients having laminectomies done by the same surgeon.

Implementation of objective criteria for diagnosis of confirmed OSI and reclassification of presumptive OSI patients.

Postoperatively, the frequency of specific adverse events within the operative site (including post-operative hematoma or bleeding; wound necrosis, dehiscence, or sinus tract; and dural tear) was 83% for documented OSI patients, contrasted with 16.7% for presumptive OSI patients (P<.01) and controls (P=.007). Median days of inpatient stay were 27 for documented OSI, contrasted with 9.5 for presumptive OSI (P=.01) and 7 for controls (P<.001).

Documented OSI patients were found to have significantly more adverse findings and longer lengths of stay than presumptive OSI patients or controls. The similarity of findings for presumptive OSI patients and controls suggests that the apparent excess frequency of OSI was caused by incorrect diagnosis. Whereas doctor's diagnosis may be useful as an initial screen for OSI, use of objective criteria for confirming OSI may avert the consequences of overdiagnosis, including excessive length of stay and unnecessary therapy, which lead to elevated healthcare costs and threaten a physician's practice.