Cocaine Detection in Urine
Cocaine's primary metabolite benzoylecgonine is detectable in urine for 24-48 hours after occasional use, but can be detected for up to 22 days in chronic heavy users (those using up to 10 g/day). 1
Detection Timeline by Usage Pattern
Occasional Users
- Standard detection window: 24-48 hours after last use for most individuals 1
- Cocaine itself is rapidly metabolized and typically undetectable within 24 hours, with peak concentrations appearing in the first urine specimen collected 2
- Benzoylecgonine has a urinary half-life of 6-8 hours 1
Chronic Heavy Users
- Detection can extend up to 22 days after last ingestion in individuals using up to 10 g/day 1
- Research using more sensitive assays (5 ng/mL cut-off) has confirmed detection windows of 17-22 days after cessation of use 3
- The mean half-life of benzoylecgonine during initial elimination is approximately 0.46 days, with levels remaining above standard cut-offs for 4.8 days and above lower thresholds for 10.5 days 4
Testing Methodology
Standard Screening Parameters
- Positive test threshold: benzoylecgonine >300 ng/mL using qualitative immunoassay 1
- Confirmatory cut-off is typically set at 100 ng/mL 3
- Benzoylecgonine is the primary target metabolite, representing approximately 16-39% of the administered dose depending on route of administration (highest with intravenous, lowest with smoked) 2
Important Considerations
- More sensitive assays (5 ng/mL cut-off) detect 51.9% more positive results than traditional 100 ng/mL cut-offs, identifying users who would otherwise be missed 3
- Quantitative methods are more expensive and potentially misleading due to individual variability in cocaine metabolism and excretion 1
- For patients unable to provide history, urine metabolite testing is appropriate, particularly in young patients with chest pain and few cardiac risk factors 1
Clinical Pitfalls to Avoid
- Do not rely solely on cocaine detection—benzoylecgonine is the metabolite that persists and should be the primary target for detection 2, 5
- Avoid assuming negative results in chronic users within the first week—detection can persist well beyond the standard 48-hour window 1, 3
- Be aware that route of administration affects metabolite excretion patterns, with intravenous use producing the highest urinary benzoylecgonine concentrations 2