Department of Gastroenterology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
School of Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon, Korea.
J Korean Med Sci. 2022 Jul 25;37(29):e227. doi: 10.3346/jkms.2022.37.e227.
The rapid urease test (RUT) is a major diagnostic tool for detecting infection. This study aimed to establish an objective method for measuring the color changes in the RUT kit to improve the test's diagnostic accuracy.
A UV-visible spectrophotometer was selected as the colorimeter; experiments were conducted in three stages to objectively identify the color changes in the RUT kit.
First, the urea broth solution showed an identifiable color change from yellow to red as the pH increased by 0.2. The largest transmittance difference detected using the UV-visible spectrophotometer was observed at a 590-nm wavelength. Second, the commercialized RUT kit also showed a gradual color change according to the pH change detected using the UV-visible spectrophotometer. Third, 13 cases of negative RUT results with a biopsy specimen and 16 of positive RUT results were collected. The transmittance detected using the UV-visible spectrophotometer showed a clear division between the positive and negative RUT groups; the largest difference was observed at a 559-nm wavelength. The lowest transmittance in the negative RUT group was 64, while the highest in the positive RUT group was 56, at the 559-nm wavelength. The UV-visible spectrophotometry reading showed a consistency of 92.7% compared with that of manual reading.
A transmittance of 60 at a 559-nm wavelength detected using UV-visible spectrophotometer can be used as a cutoff value for interpreting RUT results; this will help develop an automatic RUT kit reader with a high accuracy.
快速尿素酶试验（RUT）是检测 感染的主要诊断工具。本研究旨在建立一种客观测量 RUT 试剂盒颜色变化的方法，以提高该试验的诊断准确性。
选择紫外-可见分光光度计作为比色计；实验分三个阶段进行，以客观识别 RUT 试剂盒的颜色变化。
首先，尿素肉汤溶液的 pH 值增加 0.2 时，颜色从黄色变为红色，有明显的颜色变化。使用紫外-可见分光光度计检测到的最大透光率差异出现在 590nm 波长处。其次，商业化的 RUT 试剂盒也根据 pH 值的变化显示出逐渐的颜色变化。第三，收集了 13 例活检标本 RUT 结果阴性和 16 例 RUT 结果阳性的病例。使用紫外-可见分光光度计检测的透光率在 RUT 结果阳性和阴性组之间有明显的区分；在 559nm 波长处观察到最大差异。RUT 结果阴性组的最低透光率为 64，而 RUT 结果阳性组的最高透光率为 56，均在 559nm 波长处。与手动读数相比，紫外-可见分光光度计读数的一致性为 92.7%。
使用紫外-可见分光光度计检测的 559nm 波长处透光率为 60 可以作为解释 RUT 结果的截断值；这将有助于开发具有高精度的自动 RUT 试剂盒读取器。
