Blood test for drugs and alcohol: what to know

A laboratory checks for substances or breakdown products included in the requested panel. Detection depends on the substance, amount, timing, metabolism, and the sample used. A result may be reported as detected, not detected, or needing confirmation. It does not automatically show why a substance was present, how a person feels, or whether they are fit to drive or work. Prescribed medicines, supplements, and some medical treatments should be disclosed because they can affect interpretation.

Ask why the test is being requested, which substances are included, how the result will be used, and who can access it. Give an accurate list of medicines and supplements. Follow collection instructions and tell the clinician if you feel unwell or are worried about withdrawal. Do not change prescribed treatment to alter a result. If testing follows a suspected poisoning, share the packaging or substance information if it is safe to do so.

Get emergency help for slow or difficult breathing, inability to wake, seizure, severe confusion, chest pain, collapse, or suspected overdose. Keep the person on their side if unconscious but breathing, and do not make them vomit. Withdrawal can also be dangerous; urgent advice is needed for severe shaking, hallucinations, seizures, or confusion. A blood test must not delay emergency treatment.

What is this panel looking for? Is confirmation testing needed? How will medicines affect interpretation? When will the result be available, and who will receive it?