Giroux Erin, Ebralidze Iraklii I, Stotesbury Theresa E
Faculty of Science, Ontario Tech University, Oshawa, Ontario, Canada.
Applied Forensic Bioscience Graduate Program, Ontario Tech University, Oshawa, Ontario, Canada.
J Forensic Sci. 2025 Sep;70(5):1733-1745. doi: 10.1111/1556-4029.70088. Epub 2025 May 19.
Rapidly, untreated whole blood undergoes a clotting cascade, making forensic research that investigates "fresh" bloodletting events difficult. In bloodstain pattern analysis research, whole blood treated with anticoagulant is often used to prolong the usability of the blood and allow for transport and experimentation to simulate pattern formation using "fresh" clot-free blood. Anticoagulants bind to clotting components, making them unavailable to participate in coagulation, preventing the formation of clots. Herein, we investigate the spectral implications of anticoagulant addition for time since deposition (TSD) estimation methods, particularly of larger volume bovine blood pools. We characterized the differences in spectral profiles of blood pools with and without a citrate-based anticoagulant (ACD-A) using visible absorbance, attenuated total reflection-Fourier transform infrared (ATR-FTIR), and X-ray photoelectron (XPS) spectroscopies. Across all methods, notable spectral differences were observed, namely the red-shift in the Soret peak maxima (visible), delayed increase in the 1532 cm peak (ATR-FTIR), and increased accessibility of iron (XPS) in pools treated with ACD-A. Principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA) were used to assess the variation in the visible absorbance and ATR-FTIR spectra over time. The blood pools differed most significantly in the first week following deposition due to the addition of water in the anticoagulant, slowed desiccation, and lack of clotting in the treated blood pools. At timepoints exceeding 1 week following deposition, the spectral profiles of the pools regained similarity. In summary, the inclusion of anticoagulants is an important consideration during experimental design and TSD estimation method development.
未经处理的全血会迅速经历凝血级联反应，这使得对“新鲜”放血事件进行法医研究变得困难。在血迹形态分析研究中，通常使用经抗凝剂处理的全血来延长血液的可用性，并便于运输和进行实验，以使用“新鲜”无凝块血液模拟形态形成。抗凝剂会与凝血成分结合，使其无法参与凝血过程，从而防止凝块形成。在此，我们研究了添加抗凝剂对沉积时间（TSD）估计方法的光谱影响，特别是对较大体积的牛血池的影响。我们使用可见吸收光谱、衰减全反射傅里叶变换红外光谱（ATR-FTIR）和X射线光电子能谱（XPS），对添加和未添加基于柠檬酸盐的抗凝剂（ACD-A）的血池的光谱特征差异进行了表征。在所有方法中，均观察到了显著的光谱差异，即在添加ACD-A的血池中，Soret峰最大值出现红移（可见光谱）、1532 cm处的峰延迟增加（ATR-FTIR）以及铁的可及性增加（XPS）。主成分分析（PCA）和偏最小二乘判别分析（PLS-DA）用于评估可见吸收光谱和ATR-FTIR光谱随时间的变化。由于抗凝剂中添加了水、干燥速度减慢以及处理后的血池缺乏凝血，血池在沉积后的第一周差异最为显著。在沉积超过1周的时间点，血池的光谱特征恢复了相似性。总之，在实验设计和TSD估计方法开发过程中，抗凝剂的加入是一个重要的考虑因素。
