Cut-off dilemma: Differences from the forensic and clinic perspective

Abstract

Opioids are a major concern in many countries due to the serious health consequences associated with their use. The United Nations Office on Drugs and Crime (UNODC) opioid crisis strategy report states that the number of people using opioids for non-medical purposes around the world has nearly doubled in the last decade and the prevalence of opioid use has increased by 76% in the same period. The same report stated that opioid use is responsible for approximately two-thirds of deaths attributed to substance use disorders worldwide. Opiates are one of the five classes of abused drugs mandated for testing in the Drug Testing Program of the Substance Abuse and Mental Health Services Administration (SAMHSA). SAMHSA regulated opiate cut-off value from 300 ng/mL to 2000 ng/mL for clinical cases only in 2010. In our country, similar legislation was made in 2016 and unfortunately, the cut-off value was increased to 2000 ng/mL not only for clinical but also for forensic cases. In this study, it is aimed to examine the effects of the opiate cut-off values of 300 and 2000 ng/mL on the toxicological analysis results. Opiate results were evaluated in terms of 300 and 2000 ng/mL cut-off values in the urine samples of the cases who applied to Ege University BATI Institute, Addiction Toxicology Laboratory between 2014–2021 with illegal substance analysis. Urine samples were accepted to the laboratory and urine integrity test was performed before analysis. Urine samples were first subjected to pre-screening analysis by immunoassay method. Confirmation analysis was performed with gas chromatography-mass spectrometry (GC-MS, Agilent 7890B) of the samples that were positive after the pre-scan analysis. A total of 11,348 cases were screened in terms of opiates and the mean age of the cases is 25.4. Of the total cases, 3.45% ( n = 392) were opiate positive. Of the total cases, 83.7% ( n = 328) were male and 16.1% ( n = 64) of them were female. When the cases were classified according to the admitted reasons for the analysis request; alcohol, substance and drug use reason were 67,3%, psychiatric disorders 20.9% and 1.5% due to war & injury and falling, 7,4% for other reasons. According to the cut-off value of 300 ng/mL, the rate of opiate positive cases between 300 < n < 2000 were 39.8%. The cut-off value of 2000 ng/mL, the rate of 2000 < n opiate positive cases were 60.2%. According to the results, if the cases between 2014 and 2021 were evaluated according to the 300 ng/mL cut-off value, treatment and/or forensic proceedings would have been applied to 156 people because they were opiate positive. However, the presence of morphine in the urine samples of forensic toxicological cases, which may cause opiate positivity can be caused by legal prescription drugs, oral use of poppy seeds, or drug use. As the intake of some codeine-containing drugs even at therapeutic amounts and ingestion of food products containing poppy seeds can give a positive opiate result with the 300 ng/mL screening cut-off value, the most appropriate thresholds should extensively studied. The cut-off values used in forensic toxicological analyzes should be paid special attention in clinical and forensic analyzes. Since the cut-off values used in clinical and forensic cases are the same, awareness is the responsibility of forensic toxicologists and the physician who evaluates them medico-legally. Even in the presence of heroin and morphine in the urine matrix, too many true positive cases can be overlooked, since the threshold value used for forensic purposes is the same as that used for clinical purposes and remains below this value.