If immunoassay screening for opiates is discordant with confirmatory results, how should it be handled?

If immunoassay screening for opiates is discordant with confirmatory results, how should it be handled?

• A. If screened positive but confirmatory negative, report as negative or inconclusive per policy; may require recollection or alternative testing.
• B. If screened positive and confirmatory positive, report as positive; no further action.
• C. If screened negative but confirmatory positive, repeat the test.
• D. If either test is inconclusive, discard the specimen.

Answer: (A)

When a screening immunoassay for opiates does not agree with the confirmatory test, the final result should follow the more specific confirmatory result and the lab policy for discordant results. Immunoassays are designed to be sensitive, so they can produce false positives due to cross-reactivity or other substances. The confirmatory test (like GC-MS or LC-MS/MS) provides higher specificity, so its result is treated as definitive. Therefore, you report the result as negative or inconclusive according to policy and consider recollection or an alternative testing approach to resolve the discrepancy. This approach avoids labeling someone positive based on a screening result that is not confirmed, and it ensures the result reflects the most reliable method available. Discarding the specimen or ignoring the discordance would not align with best practice.

When a screening immunoassay for opiates does not agree with the confirmatory test, the final result should follow the more specific confirmatory result and the lab policy for discordant results. Immunoassays are designed to be sensitive, so they can produce false positives due to cross-reactivity or other substances. The confirmatory test (like GC-MS or LC-MS/MS) provides higher specificity, so its result is treated as definitive. Therefore, you report the result as negative or inconclusive according to policy and consider recollection or an alternative testing approach to resolve the discrepancy. This approach avoids labeling someone positive based on a screening result that is not confirmed, and it ensures the result reflects the most reliable method available. Discarding the specimen or ignoring the discordance would not align with best practice.