Cost and utility of routine admission laboratory testing for psychiatric inpatients.

We retrospectively evaluated the cost and utility of routine laboratory testing for psychiatric patients admitted to an acute inpatient hospital. Medical records were reviewed for 252 patients accounting for 305 sequential admissions over a recent 3-month period. Of the patient population, 49.6% had one or more coexisting medical illnesses. Overall, 6% of the abnormal laboratory findings resulted in changes in medical management: 49.2% of complete blood counts were abnormal, and 11.6% led to changes in medical management. Of the 20-factor blood chemistry analyses, 86.2% were abnormal, and 4.7% led to changes in medical management. Of the urinalyses, 85.3% were abnormal, and 2.2% led to changes in medical management. Of 277 screening syphilis titers, 5 were positive but only 1 was a potential new finding. The average cost to the facility for laboratory testing was $65 per patient admission, and the average cost per change in medical management resulting from the laboratory studies was $1070.