Influence of clinical pharmacist consultations on the use of drug blood level tests.

The effect of a controlled-ordering program (prior authorization by a clinical pharmacist) on the number and cost of drug blood level assays performed at the Truman Medical Center (Kansas City, MO) was studied. Drug assay orders for aminoglycosides, phenobarbital, phenytoin, quinidine, theophylline, salicylate, thiocyanate, and propranolol, laboratory costs, and hospital census were reviewed retrospectively. The programs compared were: (1) control (July to December 1977)--drug blood level assays were ordered at physicians' discretion, and (2) study (January 16, 1978 to January 15, 1979)--all pharmacokinetic assays had to be approved by a pharmacist. A significant (p less than 0.001) reduction in the number of assays performed per month (40%) and in the assay cost per month (44%) occurred during the study period. The program was estimated to save $12,086.61 annually. The policy of requiring pharmacist approval of drug assay orders reduced the improper use and cost of pharmacokinetic monitoring.