Cannabis (THC) (Marijuana) – Qualitative Test

Sample Type: Urine, Spot

Overview:
The qualitative cannabis (THC) test is a urine-based screening used to detect the presence of tetrahydrocannabinol (THC), the psychoactive compound in marijuana. This test identifies whether THC metabolites are present in the urine, indicating recent use of cannabis, but it does not measure the amount or pinpoint the time of use precisely.

Purpose and Use:
This test is primarily used for:

Drug screening programs (e.g., workplace, school, sports)

Clinical monitoring in substance abuse treatment or pain management

Legal or forensic evaluations

Pre-employment or random testing

Mechanism:
After cannabis is consumed, THC is metabolized by the liver into several compounds, notably 11-nor-9-carboxy-THC (THC-COOH), which is excreted in the urine. The qualitative test detects these metabolites using immunoassay techniques, typically providing a positive or negative result based on a set cutoff value (usually 50 ng/mL).

Interpretation:

Positive Result: Indicates recent cannabis use. The detection window can vary:

Occasional users: 1–3 days

Moderate users: up to 7–10 days

Chronic users: 30 days or more

Negative Result: No detectable THC metabolites at or above the cutoff level.

Limitations:

This test does not indicate impairment, frequency of use, or the amount consumed.

False positives can occur due to certain medications or cross-reactivity.

Confirmatory testing (e.g., GC-MS or LC-MS) is often required for legal or employment-related cases.