Drug Induced Modifications of Laboratory Test Values

Abstract

Effective implementation of drug use control by the pharmacist in the clinical setting requires that he he alert to current or previous drug therapy which may interfere with or alter the results of laboratory tests. Laboratory test values may vary according to the timing of collection of the sample, the method of determination, and the patient's exercise, food intake or emotional disturbances. Drugs can affect laboratory test values in several ways: physiological alteration of the level in normal body fluids of the substance being tested, chemical reaction with the test reagents, chemical or physical interference due to metabolic derivatives, and alterations due to pharmacologic side effects or toxicity.

Over 1500 citations abstracted from the American Hospital Formulary Service, Micro-Tel, the Journal of Clinical Pathology, Side Effects of Drugs, The Medical Letter and other sources are reviewed and tabulated. Relationships between drug families and specific laboratory tests are noted. Monitoring patient therapy for drug use Control should include a review of laboratory test values for possible drug-induced modifications.