Internal Gastroenterology Department.
Department of Bioanalytical Instrumentation, CEITEC Masaryk University.
J Clin Gastroenterol. 2019 May/Jun;53(5):355-360. doi: 10.1097/MCG.0000000000001066.
To evaluate the analytical parameters of a lateral flow (LF) pepsin immunoassay (Peptest) and assess its suitability in the diagnostics of gastroesophageal reflux disease (GERD).
Peptest is a noninvasive assay to analyze pepsin in saliva, intended for use in GERD diagnostics. Although commercialized, fundamental studies on its performance are missing. The assay therefore requires basic analytical parameter evaluation to assess its suitability in clinical practice.
Assay reaction's time dependence, reader device repeatability, and individual LF devices and longitudinal pepsin concentration reproducibility in individual subjects was evaluated. Salivary pepsin was analyzed in 32 GERD patients with extraesophageal reflux symptoms and 13 healthy individuals.
The assay's signal increase is not completed at the recommend readout time and continues to increase for another 25 minutes. The relative standard deviation of measurement was good when using the same LF device, ranging from 2.3% to 12.9%, but the reproducibility of 10 different individual LF devices was poor. The random error when analyzing the same saliva sample on 10 LF devices was as high as 36 ng/mL and this value is thus suggested as the positivity cut-off. Pepsin concentration in individual subjects during a 10-day period varied significantly. The sensitivity of the Peptest was 36.8% in the group with acid reflux and 23.1% in the group with weakly acid reflux. The specificity was 61.5%.
The Peptest assay's sensitivity and specificity is low, the results are highly variable and it should not be used as a near-patient diagnostic method in primary care.
评估侧向流动（LF）胃蛋白酶免疫测定（Peptest）的分析参数，并评估其在胃食管反流病（GERD）诊断中的适用性。
Peptest 是一种分析唾液中胃蛋白酶的非侵入性检测方法，旨在用于 GERD 诊断。尽管已经商业化，但缺乏对其性能的基础研究。因此，该检测需要进行基本的分析参数评估，以评估其在临床实践中的适用性。
评估了检测反应的时间依赖性、阅读器设备的重复性以及个体 LF 设备和个体受试者中纵向胃蛋白酶浓度的重现性。对 32 例有食管外反流症状的 GERD 患者和 13 例健康个体进行了唾液胃蛋白酶分析。
检测的信号增加在推荐的读数时间内并未完成，并且在另外 25 分钟内继续增加。当使用相同的 LF 设备时，测量的相对标准偏差很好，范围为 2.3%至 12.9%，但 10 个不同个体 LF 设备的重现性很差。在 10 个 LF 设备上分析相同唾液样本时的随机误差高达 36ng/mL，因此建议将该值作为阳性截断值。在 10 天期间，个体受试者的胃蛋白酶浓度变化很大。Peptest 在酸反流组中的灵敏度为 36.8%，在弱酸性反流组中的灵敏度为 23.1%。特异性为 61.5%。
Peptest 检测的灵敏度和特异性较低，结果变化较大，不应用于初级保健中的床边诊断方法。
