What is the initial screening cutoff for marijuana?

• A. 15 confirm
• B. 50 Ng/dl
• C. 500 Ng/dl
• D. 2-3 days

Answer: (B)

Initial screening of marijuana uses a fixed cutoff to decide which specimens move on for confirmation. The standard threshold for a urine immunoassay screen is 50 ng/mL of THC-COOH. Any result at or above this level flags the sample for a confirmatory test (such as GC-MS or LC-MS/MS), which has its own lower cutoff around 15 ng/mL. The other options don’t fit because 15 ng/mL is the confirmatory, not the screening, value; 500 ng/dL is not the established screening threshold and uses an unusual unit; and 2–3 days refers to a detection window, not a cutoff.