Department of Pathology, Rush University Medical Center, Chicago, IL.
Core Laboratory, St. Louis Children's Hospital, St. Louis, MO.
J Appl Lab Med. 2022 Mar 2;7(2):409-420. doi: 10.1093/jalm/jfab157.
Drug screening by immunoassay is common in pediatric populations. However, false-positive and -negative results due to antibody cross-reactivity and dilute urine are frequent and underappreciated. Accurate ascertainment of drug exposure in children has significant clinical and medico-legal consequences.
We developed and characterized an LC-MS/MS drug screening assay to supplant immunoassay and detect 38 compounds at the lowest concentrations distinguishable from analytic noise. Once implemented, we conducted a retrospective analysis of 3985 pediatric urine drug screens performed a year before (n = 1663) and after (n = 2322) implementation to examine the frequency and breadth of drug detection in our pediatric population.
Using immunoassay, 23% (293/1269) of samples from the general pediatric and 37% (147/394) of nursery populations had presumptively positive results. Of the presumptive positive compounds, 85% (288/338) from the general pediatric population and 40% (65/162) from the nursery cohort were confirmed by mass spectrometry. After LC-MS/MS implementation, 31% (628/2052) of general pediatric, and 18% (48/270) of the nursery samples were positive for 1 or more compounds. In the nursery population, immunoassays over-detected the presence of THC but under-detected exposure to cocaine.
A broadly targeted, analytically sensitive LC-MS/MS drug screening assay detects a larger number and variety of compounds in a single step compared to a screen-then-confirm approach initiated by immunoassay in our pediatric population. Rapid delivery of accurate results enables timely, appropriate disposition of patients in a variety of settings including the emergency department and labor/delivery.
免疫分析法常用于儿科人群的药物筛选。但是，由于抗体交叉反应和尿液稀释，经常会出现假阳性和假阴性结果，且这些结果未被充分认识。准确确定儿童的药物暴露情况具有重要的临床和医疗法律后果。
我们开发并表征了一种 LC-MS/MS 药物筛选检测方法，以替代免疫分析法，并以可与分析噪声区分的最低浓度检测 38 种化合物。一旦实施，我们对实施前一年（n=1663）和实施后一年（n=2322）进行了 3985 例儿科尿液药物筛选的回顾性分析，以检查我们儿科人群中的药物检测频率和广度。
使用免疫分析法，普通儿科人群的 23%（293/1269）和托儿所人群的 37%（147/394）的样本有推定阳性结果。在普通儿科人群中，85%（288/338）的推定阳性化合物和 40%（65/162）的托儿所队列中的化合物通过质谱法得到确认。LC-MS/MS 实施后，2052 例普通儿科样本中的 31%（628/2052）和 270 例托儿所样本中的 18%（48/270）对 1 种或多种化合物呈阳性。在托儿所人群中，免疫分析法过度检测了 THC 的存在，但可卡因的暴露情况则被低估。
与从免疫分析法开始的筛选-确认方法相比，广泛靶向、分析灵敏的 LC-MS/MS 药物筛选检测方法在单次检测中可检测到更多种类和更多数量的化合物。准确结果的快速提供使患者能够在各种环境中（包括急诊科和分娩室）及时、适当地进行处理。
