Cocaine Detection Windows Across Biological Specimens
For typical cocaine users, benzoylecgonine (the primary metabolite) is detectable in urine for 24-48 hours after use, while chronic heavy users may test positive for up to 22 days. 1, 2
Urine Testing (Most Common Method)
Standard detection timeline:
- Occasional users: 24-48 hours after last use 1, 2
- Chronic heavy users (up to 10 g/day): Up to 22 days after last use 1, 2
- Benzoylecgonine urinary half-life: 6-8 hours 1, 2
- Mean time to first negative urine after intranasal use: 43.6 ± 17.1 hours (range 16-66 hours) 2
Testing methodology:
- Standard immunoassay cut-off: benzoylecgonine >300 ng/mL 1, 2
- Lower cut-offs (5 ng/mL) can detect 51.9% more positive results but are not standard practice 3
- Quantitative methods are more expensive and potentially misleading due to individual metabolic variability 1
Blood Testing
Detection window: 2-12 hours after use, most useful for acute presentations and correlating impairment levels 4, 2
- Blood testing is invasive, costly, and requires specially trained personnel 4
- Best used in emergency situations when recent use and level of impairment need correlation 4
Saliva (Oral Fluid) Testing
Detection window: 24-48 hours after use 4, 2
- Less invasive than blood testing and captures recent drug exposure that may not yet be detectable in urine 4, 2
- Point-of-care tests are available 4
- Smoking and methods used to stimulate saliva production may affect results 4
Sweat Testing
Detection window: 48 hours before patch application and continuously throughout 3-7 day wear period 2
- Patches detect both pre-application use (within 48 hours) and ongoing use during wear 4, 2
- Environmental contamination can lead to false-positive results 4, 2
- Sweat swipes may detect use within past 24 hours 4
Hair Testing
Detection window: Up to 90 days (analyzing first 3 cm of hair) 2
- Critical limitation: Cannot detect use within the previous 7-10 days due to time needed for drug incorporation into hair matrix 2
- Hair analysis provides a wider window of detection than urinalysis and shows merit for confirming cocaine use 5
- Limit of quantification: 0.1 ng/mg for cocaine, 0.5 ng/mg for benzoylecgonine 6
Clinical Pitfalls to Avoid
Timing is critical:
- When drug-facilitated scenarios are suspected, collect specimens immediately—even before completing history and physical examination—to avoid missing the detection window 4, 2
- Coordinate specimen collection with sexual assault response teams and law enforcement when applicable 4
Testing limitations:
- Standard drug-screening panels often omit specific cocaine metabolites; verify which substances your laboratory can detect 2
- Flunitrazepam and similar drugs are not identified in routine benzodiazepine tests 4
- Document chain of custody for any specimens intended for legal proceedings 4
Interpretation considerations: