Centre for Biospectroscopy, Monash University, Clayton, 3800, Victoria, Australia.
Analyst. 2017 Apr 10;142(8):1192-1199. doi: 10.1039/c6an02075e.
Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR-FTIR) has the potential to become a new diagnostic tool for malaria and other diseases. For point-of-care testing, the use of ATR-FTIR in malaria diagnosis enables the analysis of blood in the aqueous state, which represents an enormous advantage by minimising the sample preparation by removing the need for cell fixation. Here we report the quantification of malaria parasitemia in human RBCs in their normal physiological aqueous state. A potential confounding variable for spectroscopic measurements performed on blood are the various anticoagulants that are required to prevent clotting. Accordingly, we tested the effects of 3 common anticoagulants; Sodium Citrate (SC), Potassium Ethylenediaminetetraacetic Acid (EDTA) and lithium heparin on plasma and whole blood in the aqueous and dry phase. Principal Component Analysis (PCA) revealed the model was heavily influenced by the anticoagulants in the case of dry samples, however, in aqueous whole blood samples, the effect was less pronounced as the water in the sample presumably diluted the amount of anticoagulant in contact with the ATR crystal. The possible influence of the anticoagulant effect on the ability to quantify parasitemia levels was tested using Partial Least Squares Regression Analysis (PLS-R). There was no influence of anticoagulants on quantification in the 0-1% range, however attempts to quantify at lower levels (0-0.1%) was best achieved with heparin compared to the other two anticoagulants. The results demonstrate ability to diagnose malaria using ATR-FTIR spectroscopy using wet RBC samples as well as underscoring the desirability to perform wet measurements as these minimise the possible confounding influence of anticoagulants used in blood collection.
衰减全反射傅里叶变换红外光谱（ATR-FTIR）有可能成为疟疾和其他疾病的新诊断工具。对于即时检测，ATR-FTIR 在疟疾诊断中的应用能够分析处于水相状态的血液，这通过最小化样品制备（去除细胞固定的需要）而具有巨大优势。在这里，我们报告了在人类 RBC 的正常生理水相状态下定量疟原虫血症。对血液进行光谱测量的一个潜在混杂变量是防止凝血所需的各种抗凝剂。因此，我们测试了 3 种常见抗凝剂对血浆和全血在水相和干燥相的影响：柠檬酸钠（SC）、乙二胺四乙酸钾（EDTA）和肝素锂。主成分分析（PCA）表明，在干燥样本的情况下，模型受到抗凝剂的严重影响，然而，在水相全血样本中，由于样本中的水可能会稀释与 ATR 晶体接触的抗凝剂的量，因此影响较小。使用偏最小二乘回归分析（PLS-R）测试了抗凝剂对定量寄生虫血症水平能力的可能影响。抗凝剂在 0-1%范围内对定量没有影响，但是，与其他两种抗凝剂相比，肝素在尝试定量更低水平（0-0.1%）时效果更好。结果表明，使用 ATR-FTIR 光谱技术可以使用湿 RBC 样本诊断疟疾，并且强调了进行湿测量的可取性，因为这可以最小化血液采集过程中使用的抗凝剂的可能混杂影响。
