The aim of this study was to develop and validate a method to generate phenol red thread tests (PRTT) due to the lack of availability of commercial PRTT. White cotton thread was dyed with phenol red (pH indicator) for 48 h, dried, cut, and sterilized. To validate its wicking ability, the thread was inserted into solutions of varying pH, flanking the pH of healthy tears, for different time intervals. To assess its diagnostic utility, PRTTs were performed on wildtype and a murine model of evaporative dry eye, knockout ( KO) mice. Two batches of PRTT were produced that had a similar appearance and function to the commercial product. testing revealed no significant differences in the wicking kinetics at any time point across the pH solutions for batch 1 and only one difference for batch 2 (pH 7.4 vs 7.8 at 5 s, = 0.029). When comparing both batches, similar wicking kinetics were found with only two significant differences identified (pH 7.6 at 40 s and pH 7.8 at 35 s, < 0.01). , our PRTT yielded similar measurements to the commercial PRTT in wildtype and KO mice and detected a significant increase in aqueous tear volume in the KO mice (commercial: = 0.015, our PRTT: = 0.002). Our method provides a reproducible diagnostic test that performs similarly to its commercial counterpart in a relevant dry eye model indicating that it can serve as a valid and reliable replacement.

中文翻译：

---

酚红线测试生成方法的开发和验证


由于缺乏商业 PRTT，本研究的目的是开发和验证一种生成酚红线测试 (PRTT) 的方法。白色棉线用酚红（pH指示剂）染色48小时，干燥，切割，灭菌。为了验证其芯吸能力，将线插入不同 pH 值的溶液中，在健康眼泪的 pH 值两侧，插入不同的时间间隔。为了评估其诊断效用，对野生型和蒸发性干眼症敲除 (KO) 小鼠模型进行了 PRTT。生产了两批与商业产品具有相似外观和功能的 PRTT。测试显示，批次 1 的 pH 溶液在任何时间点的芯吸动力学均没有显着差异，而批次 2 仅有一处差异（5 秒时 pH 7.4 与 7.8，= 0.029）。比较两个批次时，发现相似的芯吸动力学，仅发现两个显着差异（40 秒时的 pH 7.6 和 35 秒时的 pH 7.8，< 0.01）。 ，我们的 PRTT 在野生型和 KO 小鼠中产生了与商业 PRTT 相似的测量结果，并检测到 KO 小鼠中水性泪液体积显着增加（商业：= 0.015，我们的 PRTT：= 0.002）。我们的方法提供了一种可重复的诊断测试，其性能与相关干眼模型中的商业对应物类似，表明它可以作为有效且可靠的替代品。