Mina Ashraf, Stathopoulos John, Sinanian Taveet, McNeice Leah, Holmes Deirdre, Fletcher Kristi-Lee, Bottero Emily, Banukumar Shanmugam, Vazquez Santiago
NSW Health Pathology, Forensic & Analytical Science Service (FASS), Toxicology Unit, Macquarie Hospital, Sydney, NSW, Australia.
Faculty of Medicine and Health, Sydney University, Sydney, NSW, Australia.
Adv Lab Med. 2021 Jun 4;2(4):550-566. doi: 10.1515/almed-2021-0026. eCollection 2021 Nov.
In the absence of sample validity testing, a healthcare provider may fail to identify a patient's adulteration of their urine sample. This study compared different methods for specific gravity (SG), pH, TECO™ Drug Adulteration Test Strip (dipstick) and oxidant assay to explain the differences and also make an informative decision on method selection.
Creatinine, SG and pH measurements are essential in sample validity testing. SG and pH automated chemical methods are compared against pH meter method, SG refractometer and dipstick method. Also, oxidant assay was compared against dipstick method.
SG chemical method agreement with refractometer is 81.9% and with dipstick method is 64.7%. The refractometer method agreement with dipstick method is 66.1%. pH chemical method agreement with pH Meter method is 74.3% and with dipstick method is 81.4%. pH meter method agreement is 85.7% with dipstick method. Results were analysed using Deming regression analysis and F-test. SG chemical method correlated better with refractometer than the dipstick method. Oxidant assay correlated well with dipstick method in detecting adulterants such as pyridinium chlorochromate, nitrite and bleach.
Varying degrees of differences were seen in the SG and pH measurements. These differences were both method and instrument dependent. The automated chemical methods are recommended alongside oxidant assay for consistency, accuracy and faster turn-around time as part of sample validity testing for drugs of abuse.
在缺乏样本有效性检测的情况下，医疗服务提供者可能无法识别患者尿液样本的掺假情况。本研究比较了比重（SG）、pH值、TECO™药物掺假检测试纸（试纸条）和氧化剂检测等不同方法，以解释差异，并就方法选择做出明智决策。
肌酐、SG和pH值测量在样本有效性检测中至关重要。将SG和pH值的自动化化学方法与pH计法、SG折射仪和试纸条法进行比较。此外，还将氧化剂检测与试纸条法进行了比较。
SG化学法与折射仪的一致性为81.9%，与试纸条法的一致性为64.7%。折射仪法与试纸条法的一致性为66.1%。pH化学法与pH计法的一致性为74.3%，与试纸条法的一致性为81.4%。pH计法与试纸条法的一致性为85.7%。使用戴明回归分析和F检验对结果进行分析。SG化学法与折射仪的相关性优于与试纸条法。在检测诸如氯铬酸吡啶鎓、亚硝酸盐和漂白剂等掺假物时，氧化剂检测与试纸条法相关性良好。
在SG和pH值测量中观察到不同程度的差异。这些差异既取决于方法也取决于仪器。作为药物滥用样本有效性检测的一部分，建议将自动化化学方法与氧化剂检测一起使用，以确保一致性、准确性和更快的周转时间。
