What is the initial screening cutoff for methamphetamine?

What is the initial screening cutoff for methamphetamine?

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

Answer: (C)

The key idea is understanding that the screening cutoff is the concentration threshold used in the initial test to flag a specimen as presumptively positive for a drug. For methamphetamine, this threshold is 500 ng/mL. If a specimen is at or above this level, it triggers a confirmatory test (typically GC-MS) to verify and quantify the drug more accurately. This cutoff balances catching true positives with limiting false positives from cross-reacting substances or medications. The other options aren’t appropriate because they either don’t represent a concentration threshold (one is a time frame, another uses a nonstandard unit), or they’re not expressed as the screening cutoff used in the initial immunoassay.

The key idea is understanding that the screening cutoff is the concentration threshold used in the initial test to flag a specimen as presumptively positive for a drug. For methamphetamine, this threshold is 500 ng/mL. If a specimen is at or above this level, it triggers a confirmatory test (typically GC-MS) to verify and quantify the drug more accurately. This cutoff balances catching true positives with limiting false positives from cross-reacting substances or medications.

The other options aren’t appropriate because they either don’t represent a concentration threshold (one is a time frame, another uses a nonstandard unit), or they’re not expressed as the screening cutoff used in the initial immunoassay.