Which laboratory process validates a drug test result after initial screening?

Which laboratory process validates a drug test result after initial screening?

• A. Screening
• B. Laboratory accreditation
• C. Confirmatory LTO
• D. Mandatory testing

Answer: (C)

Validation after screening hinges on a confirmatory test that uses a more specific method to positively identify and quantify the drug, ensuring the result is accurate and defensible. Screening tests, like immunoassays, can give false positives because they may react with similar substances. The confirmatory step uses a highly specific analytics method—typically GC-MS or LC-MS/MS—to confirm the exact drug and its amount. This two-step approach moves from a broad flag to a definitive result, which is essential for making reliable decisions. The other options describe the initial screening, quality systems, or policy, not the process that validates and finalizes the result.

Validation after screening hinges on a confirmatory test that uses a more specific method to positively identify and quantify the drug, ensuring the result is accurate and defensible. Screening tests, like immunoassays, can give false positives because they may react with similar substances. The confirmatory step uses a highly specific analytics method—typically GC-MS or LC-MS/MS—to confirm the exact drug and its amount. This two-step approach moves from a broad flag to a definitive result, which is essential for making reliable decisions. The other options describe the initial screening, quality systems, or policy, not the process that validates and finalizes the result.