A computer based intervention to reduce unnecessary serologic testing

Objective. Laboratory testing is important in the evaluation of patients wi th possible systemic rheumatic disease, but uncritical use of any test may result in misleading information and unnecessary costs. We attempted to red uce the number of unnecessary antinuclear antibody, rheumatoid factor, and complement level tests ordered by house officers at a large teaching hospit al, where inpatient orders are written through a computer based order entry system. Methods. We conducted a prospective cohort study of an interactive test ord ering program. The intervention consisted of displaying post-test probabili ty estimates during the usual physician order entry session. These estimate s were based on pretest probabilities entered by the ordering physician and sensitivities and specificities derived from a literature review. Another group of test orders did not prompt the intervention and were considered co ntrols. The outcome of interest was the percentage of tests canceled in the intervention group versus the control group. Results. Eleven percent (11/99) of intervention orders were canceled. versu s only one order among 236 controls (p = 0.001). However, there was no asso ciation between the physicians' pretest probability estimates and whether t est orders were canceled (p = 0.59). Additionally, 43 of the 335 orders (13 %) yield ed positive tests, but only 4 patients (1%) were given new diagnos es of rheumatic disease. Conclusion. The computer based intervention significantly reduced orders fo r antinuclear antibody and rheumatoid factor levels by 10%. Further reducti ons without clinical harm are probably possible, since the yield of testing for new rheumatic diseases was low.