How to use toxicology screening tests

How to interpret urine toxicology tests

“…A urine toxicology screen is a qualitative test of specific drugs or their metabolites in the urine 2. Substances are detected in the urine by enzymatic immunoassays (EIAs).…”

“…The presence of drugs at a detectable level in the urine is generally short lived, although metabolites may be present for longer 2 3. Different substances remain in the urine for different lengths of time after ingestion, and this influences interpretation.…”

“…A positive test may suggest exposure to a substance, however that does not mean that the signs or symptoms demonstrated are attributable to that substance. There is a danger that with a positive screen other diagnoses may be missed, and it is important to remember that a urine toxicology screen is not a diagnostic test 2 3…”

“…Most cases of toxin exposure in the under 12s are accidental, whereas the teenage population tend to have intentional exposures 2. The adolescent group carry higher rates of morbidity and mortality following exposure.…”

A 12-year-old Bella Donna

“…Antidepressents, such as selective seratonin reuptake inhibitors (SSRI) and tricyclic antidepressants (TCA), are not routinely screened for on a urine toxicology ‘screening’ test 2. It is important to request a screen for the specific drugs that are in keeping with the clinical presentation, and if in doubt, to discuss with the biochemical scientists on duty.…”