K他命尿液檢驗假陽性探究及檢測方法提升

K他命本為麻醉藥劑，但近20多年來K他命以「娛樂用藥」盛行於台灣、香港與大陸沿海，而近年來更出現了許多變種K他命類緣物毒品。K他命在台灣主要使用方式為菸吸，其次為鼻吸。在檢驗方面，多年來國內外現有的K他命免疫抗體皆有嚴重的假陽性問題，因此本研究首先以2017年至2023年常規K他命檢驗結果進行統計，發現免疫初步檢驗的假陽性率竟然高達六成左右。為改善此困境，進而改進現有確認檢驗方法，將K他命目前已知最下游尿液代謝物-去氫去甲基K他命(DHNK)加入氣相層析質譜儀偵測，以提升追溯期至5-6天，並以575件K他命初篩陽性檢體進行評估。結果發現約有兩成半的檢體，原判定為確認檢驗陰性結果，但卻可測得DHNK。亦即這些個案其實都有吸食K他命。納入DHNK後，K他命確認檢驗陽性率可從36.8%，大幅提升至57.0 % (以100 ng/ml為閾值)與61.8 % (以定量極限25 ng/ml為閾值)。最後是建立變種的K他命之檢驗方法，針對較流行的新型態K他命，如:去氯K他命及加氟去氯K他命，並將它們加入常規K他命之確認檢驗方法中。而無標準品之代謝物，則以真實檢體反推其質譜碎片圖譜，因此具更長期追溯能力之F-DHNK與H-DHNK也在本研究中被建立，未來將可同時進行原態與變種的K他命之尿液檢驗，進一步提升檢驗之毒品廣度與追溯時間。

Ketamine originally served as an anesthetic drug. But in the past two decades, it has become very prevalent in Taiwan, Hong Kong, and coastal China as a recreational drug. In Taiwan, ketamine user is primarily smoked and secondarily snorted. Various ketamine analogs such as deschloroketamine (DCK, HK) and fluorodeschloroketamine (FDCK, FK) have also emerged recently. Unfortunately, almost immunoassays of ketamine show severe false positive results. Therefore, the screening test results from 2017 to 2023 was investigated and found a high false positive rate of up to 63.2%. Furthermore, the analysis of the downstream metabolite of ketamine,DHNK, has been added into the confirmation test for extending the detection window to 5- 6 days. 575 screening positive samples were tested for DHNK. The results revealed that nearly 25% of samples tested positive for DHNK. It means these cases had actually used ketamine. The positive rate of confirmation test can be significantly upgraded from 36.8 % to 57.0 or 61.8% (threshold set as 25 or100 ng/ml). Lastly, a GC/MS confirmation test was developed for emerging ketamine analogs of HK and FK. Real samples are used to trace back the chromatography and mass spectrum of their metabolites, especially for F-DHNK and H-DHNK. This approach progressively expands the breadth and depth of the method for the new generation of ketamine analogs.