Karakukcu, CigdemCiraci, Mehmet ZahidKocer, DeryaFaydali, Mine YuceSerdar, Muhittin Abdulkadir2023-02-212023-02-212021-01-0110.1515/tjb-2020-0614https://hdl.handle.net/11443/2259http://dx.doi.org/10.1515/tjb-2020-0614Objectives: To obtain optimal immunoassay screening and LC-MS/MS confirmation cut-offs for opiate group tests to reduce false positive (FP) and false negative (FN) rates. Methods: A total of 126 urine samples, -50 opiate screening negative, 76 positive according to the threshold of 300 ng/mL by CEDIA method - were confirmed by a full-validated in-house LC-MS/MS method. Sensitivity, specificity, FP, and FN rates were determined at cut-off concentrations of both 300 and 2,000 ng/mL formorphine and codeine, and 10 ng/mLfor heroinmetabolite 6-mono-acetyl-morphine (6-MAM). Results: All CEDIA opiate negative urine samples were negative for morphine, codeine and 6-MAM. Although sensitivity was 100\% for each cut-offspecificity was 54.9\% at CEDIA cut-off 300 ng/mL vs. LC-MS/MS cut-off 300 ng/mL and, 75\% at CEDIA cut-off 2,000 ng/mL vs. LC-MS/MS cut-off 2,000 ng/mL. False positive rate was highest (45.1\%) at CEDIA cut-off 300 ng/mL. At CEDIA cut-off 2,000 ng/mL vs. LC-MS/MS cut-off 300 ng/mL, specificity increased to 82.4\% and FP rate decreased to 17.6\%. All 6-MAM positive samples had CEDIA concentration >= 2,000 ng/mL. Conclusions: 2,000 ng/mL for screening and 300 ng/mL for confirmation cut-offs are the most efficient thresholds for the lowest rate of FP opiate results.6-MAMcodeineconfirmationcut-offimmunoassayLC-MS/MSmorphineopiatescreeningArticleWOS:000712261700015