Enzymatic assay for urine lactose in the assessment of recent intravenous abuse of buprenorphine.

Urine samples were analyzed for lactose to investigate if elevated lactose concentrations indicate recent (< 48 hours) intravenous abuse of substances containing lactose as an excipient. Elevated lactose levels were found in samples given by patients who had recently injected substances intravenously, verified by fresh injection marks. Urine lactose assay can support clinical and toxicological findings when assessing substance abuse.