Substituted Specimen
A urine specimen whose creatinine and specific gravity values fall outside the physiologically possible range for human urine, indicating it was swapped or replaced.
Key Facts
- A specimen with creatinine below 2 mg/dL and specific gravity outside the human range
- Indicates the sample is not consistent with human urine (e.g., synthetic urine or water)
- A verified substituted result on a DOT test is a refusal to test
- Detected by routine specimen validity testing at the laboratory
A substituted specimen is reported when laboratory analysis shows creatinine below 2 mg/dL together with specific gravity below 1.0010 or at or above 1.0200 — values inconsistent with human urine. This typically indicates the donor supplied synthetic urine, someone else’s urine, or a heavily manipulated sample. Under 49 CFR Part 40, a verified substituted specimen is reported as a refusal to test, carrying the same consequences as a verified positive result. Collection-site safeguards — temperature checks within four minutes, no coats or bags in the restroom, bluing agent in the toilet — exist largely to deter substitution.
BlueHive Marketplace
Need DOT Drug Test (5-panel) for your team?
Order from 20,000+ providers across all 50 states. BlueHive schedules the visit, coordinates the paperwork, and returns results to one dashboard.
Related Services
Related Industries
50
States Covered
Need This Service?
Find certified occupational health providers offering this service in your area. Over 20,000 locations nationwide.
Simplify Occupational Health
BlueHive manages occupational health services so you can focus on your workforce.