During testing, a urine specimen migrates upward by capillary action. Marijuana, if present in the urine specimen below 50 ng/mL, will not saturate the binding sites of the antibody coated particles in the test strip. The antibody coated particles will then be captured by immobilized marijuana conjugate and a visible colored line will show up in the test line region. The colored line will not form in the test line region if the marijuana level is above 50 ng/mL because it will saturate all the binding sites of antimarijuana antibodies.
A drug-positive urine specimen will not generate a colored line in the test line region because of drug competition, while a drug-negative urine specimen will generate a line in the test line region because of the absence of drug competition.
To serve as a procedural control, a colored line will always appear at the control line region if the test has been performed properly.
The Marijuana Drug Test detection time-urinalysis
| Light smoker or acute dosage | 1-3 days |
| Moderate use (4x / week) | 3-5 days |
| Heavy smoker (daily) | 10 days |
| Heavy, chronic use (5+ joints/day) | 10-21+ days |
| Oral ingestion | 1-5 days |
Passive inhalation of marijuana. In general, routine passive exposure to marijuana smoke will not result in a positive result for carboxy-THC. Only under unrealistic conditions, a person may test positive for carboxy-THC, but concentrations are generally below the routine cut off levels.
Substances or Conditions which can cause false positives THC Marijuana Drug Test
- Dronabinol (Marinol)
- Ibuprofen; (Advil, Nuprin, Motrin, Excedrin IB etc)
- Ketoprofen (Orudis KT)
- Kidney infection (Kidney disease, diabetes) Liver Disease
- Naproxen (Aleve)
- Promethazine (Phenergan, Promethegan)
- Riboflavin (B2, Hempseed Oil)
