Detection time of drugs of abuse in urine

Estimating the detection time of a drug in urine is complex because of many different influencing factors and the lack of experimental data. Detection times vary depending on dose and route of administration, metabolism and c haracteristics of the screening and confirmation assays. Using a cut-off value of 1000 ng/mL, urinary samples can be positive for am phetamine for up to 5 days after intake of the drug. At the lower 300 ng/mL cut-off, amphetamine will be detectable one day longer. Very few data are available for designer amphetamines. After smoking one marijuana cigarette, THCCOOH (9-carboxy-Delta (9) tetrahy drocannabinol) is detectable (using a screening cut-off of 50 ng/mL) for 2- 4 days. More frequent use will be detectable for almost 1 month, exceptiona lly 3 months. Immunoassays to detect cocaine are targeted against the metabolite benzoyle cgonine and use a cut-off of 300 ng/mL. An intravenous dose of 20 mg cocain e can be detected for 1.5 days. Street doses (administered via different ro utes) are detectable up to 1 week, and extremely high doses up to 3 weeks. Heroin rapidly metabolises to 6-acetylmorphine and morphine. Immunoassays f or heroin are calibrated with morphine but important cross-reactivity occur s and positive results must be confirmed by GC-MS. Experimental data for to tal morphine using a cut-off of 300 ng/mL suggest a detection time of 1 to 1.5 days for relatively low doses of heroin (3-12 mg) administered via IV, IN or IM route.