Creatinine (Cr) is a biochemical waste molecule generated from muscle metabolism and primarily cleared from the bloodstream by the kidneys. If kidney function declines, Cr levels in the blood tend to increase. Therefore, Cr serves as an indicator of kidney function. In this work, we present a simple method for the rapid screening for impaired renal function based on the subject’s Cr concentration. In our setup, broadband white light is delivered to a finger clamp through a fiber-optic cable to illuminate the patient’s finger. The light is transmitted through the finger and collected by a second optical fiber coupled to a visible–near-infrared (VisNIR) spectrometer which covers the spectral range from 400[Formula: see text]nm to 1100[Formula: see text]nm. During the calibration process, the transmitted spectra acquired from 60 patients were measured. An average was calculated using the peak level of the transmitted, diffused intensity at three different wavelengths to create a “Cr intensity index”. Patients were divided into five groups according to their Cr concentration levels, ranging from 1[Formula: see text]mg/dL to 13[Formula: see text]mg/dL. Our observations indicated that each group featured a unique spectral fingerprint. Next, we tested the index on 20 patients not included in the calibration procedure (unknown samples). We were able to classify patients into groups according to their Cr level with moderate prediction accuracy ([Formula: see text]) and mean screening error of up to 16%. Future efforts will evaluate the accuracy of this approach with larger patient populations representing a broad range of Cr concentration. Still, this preliminary work is an essential step toward developing this useful noninvasive Cr screening platform using NIR light spectroscopy.

中文翻译：

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漫透射光谱结合光谱峰值平均作为无创肌酐筛查的潜在工具

肌酐 (Cr) 是一种由肌肉代谢产生的生化废物分子，主要由肾脏从血液中清除。如果肾功能下降，血液中的 Cr 水平往往会升高。因此，Cr 可作为肾功能的指标。在这项工作中，我们提出了一种基于受试者 Cr 浓度快速筛查肾功能受损的简单方法。在我们的设置中，宽带白光通过光纤电缆传送到手指夹，以照亮患者的手指。光通过手指传输并由耦合到可见-近红外 (VisNIR) 光谱仪的第二根光纤收集，该光谱仪的光谱范围从 400[公式：参见文本]nm 到 1100[公式：参见文本]nm。在校准过程中，测量了从 60 名患者获得的透射光谱。使用三个不同波长的透射、扩散强度的峰值水平计算平均值，以创建“Cr 强度指数”。患者根据Cr浓度水平分为5组，范围从1[公式：见正文]mg/dL到13[公式：见正文]mg/dL。我们的观察表明，每组都具有独特的光谱指纹。接下来，我们在校准程序中未包括的 20 名患者（未知样本）上测试了该指数。我们能够根据患者的 Cr 水平以中等预测准确度（[公式：见正文]）将患者分组，平均筛查误差高达 16%。未来的努力将评估这种方法的准确性，更大的患者群体代表广泛的 Cr 浓度。尽管如此，这项初步工作仍然是使用 NIR 光谱开发这种有用的非侵入性 Cr 筛选平台的重要一步。