Saliva has garnered a lot of interest as a non-invasive, easy to collect, and biochemical rich sample for attenuated total reflection–Fourier transform infrared spectroscopy (ATR-FTIR) based disease diagnosis. Although a large number of studies have explored its potential, the preparation methods used differ greatly. For large scale clinical studies to aid translation into clinics, the collection/processing methodology needs to be standardized. Therefore, in this study, we explored different saliva collection (spitting, method A/cotton soaking, method B) and processing protocols (unprepared, TS; supernatant from the centrifugation, CS; and drying, C) to find which gives the best ATR-FTIR signals. Analysis showed highest proteins, carbohydrates, amino acids, and nucleic acid + proteins/lipids in BTS, BCS, ACS, and BC, respectively. Notably, only BC shows a 1377 cm⁻¹ nucleic acid band that is also uniquely identified in multivariate analysis. We conclude that the collection-processing protocol should be based on a biochemical component that best gives a differential diagnosis.

唾液作为一种非侵入性、易于收集且富含生化物质的样本，用于基于衰减全反射傅里叶变换红外光谱 (ATR-FTIR) 的疾病诊断，引起了广泛的关注。尽管大量研究已经探索了其潜力，但所使用的制备方法差异很大。对于帮助转化为临床的大规模临床研究，收集/处理方法需要标准化。因此，在本研究中，我们探索了不同的唾液采集（吐痰，方法 A/棉花浸泡，方法 B）和处理方案（未制备，TS；离心上清液，CS；干燥，C），以找出最佳 ATR -FTIR 信号。分析显示，BTS、BCS、ACS 和 BC 中的蛋白质、碳水化合物、氨基酸和核酸+蛋白质/脂质分别最高。值得注意的是，只有BC显示出1377 cm ^{-1 的}核酸条带，该条带也在多变量分析中被唯一识别。我们的结论是，收集处理方案应基于最能提供鉴别诊断的生化成分。