Use of a drug-screening service in an inner-city teaching hospital.

Experience in urinary drug screening at St Vincent's Hospital, Melbourne, was evaluated over a period of 12 months after the introduction of a commercially available thin-layer chromatographic system which expanded the capabilities and improved the efficiency of the service. Specimens from 167 patients were screened when either drug overdose, or drug abuse, or poor compliance with prescribed medications was suspected. Screening was also undertaken to aid solution of diagnostic problems by excluding the possibility of drug ingestion. Benzodiazepines, barbiturates, and tricyclic antidepressants represented the drug groups which were most frequently detected. Multiple drug use was common with the mode and median number of drugs taken being two. For 75% of the patients studied, relevant information about drug intake was either unreliable or not obtainable before drug screening. Retrospective examination of the case histories showed that drug screening assisted in arriving at diagnostic or management decisions for at least 66% of the patients.