Pacific Laboratory Medicine Services
* Department of Clinical Pharmacology, Royal North Shore Hospital, Sydney, Australia.

In order to determine the usefulness of drug screening in the Accident and Emergency department, a prospective study was conducted of 93 urine drug screens. Royal North Shore is a major university teaching hospital in Sydney, serving a population of 750,000. Urine specimens were collected from overdose admission patients on admission, and stored for future analysis. Patients were treated symptomatically. Analysis of the specimens, using EMIT, high performance thin layer chromatography and gas chromatography-mass spectrometry, revealed the presence of benzodiazepines, paracetamol, tricyclics and minor medications, none of which would have influenced acute patient management. Furthermore, many drugs were detected as a sequelae of treatment, for example, lignocaine, diazepam and thiopentone. In 47% of cases, drugs detected matched those stated to have been taken, 28% showed fewer drugs. Overall in 75% of cases no other drugs were identified.

The study demonstrated the need to use toxicology facilities judiciously, but justifies the practice of measuring blood paracetamol concentrations in all overdose patients.