In analytical chemistry serum as well as plasma are recommended as sample material of choice. However, blood processing for the generation of serum or plasma is rather different. Whether plasma or serum is the preferable sample material is still controversial discussed. We performed in paired samples three UHPLC-mass spectrometry-driven metabolomics studies. In study 1 metabolite profiles of serum vs plasma were compared. 46% out of 216 identified metabolites showed significant different levels (paired Wilcoxon signed-rank test, p < 0.05, FDR <0.01) with only three metabolites (methionine, C2:0- and C3:0-carnitine) showing lower levels in serum. In study 2 comparison of three different serum blood collection tubes revealed that coagulation and associated processes distinctly alter metabolite levels depending on the tube-specific clotting process. Most pronounced differences were found for the dipeptide phenylalanine-phenylalanine (highest levels in silicate containing serum blood collection tubes). In study 3 possible adverse effects of platelets, which still remain in standard plasma even after correct processing, were investigated. No differences in a pattern of 216 metabolites were detected in the comparison of standard and platelet-free plasma (PFP). Our results give novel insights in fundamental differences between serum and plasma, thereby providing valuable information for analytical chemists for decision making to either use serum or plasma before starting complex and time-consuming analytical investigations.

中文翻译：

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血清或血浆，有什么区别？促进代谢组学研究及其他研究的样品材料选择决策过程的调查

在分析化学中，推荐使用血清和血浆作为样品材料。然而，用于产生血清或血浆的血液处理却大不相同。血浆或血清是否是优选的样品材料仍存在争议。我们在配对样品中进行了三项 UHPLC 质谱驱动的代谢组学研究。在研究 1 中，比较了血清与血浆的代谢物谱。216 种已鉴定代谢物中的 46% 显示出显着不同的水平（配对 Wilcoxon 符号秩检验，p < 0.05，FDR < 0.01），只有三种代谢物（蛋氨酸、C2:0- 和 C3:0-肉碱）在血清中显示出较低的水平. 在研究 2 中，对三种不同的血清采血管进行比较表明，凝血和相关过程明显改变了代谢物水平，具体取决于管特异性凝血过程。发现二肽苯丙氨酸-苯丙氨酸（含硅酸盐的血清采血管中含量最高）的差异最为显着。在研究 3 中，研究了即使经过正确处理仍保留在标准血浆中的血小板可能的不利影响。在标准和无血小板血浆 (PFP​​) 的比较中，没有检测到 216 种代谢物的模式差异。我们的结果为血清和血浆之间的根本差异提供了新的见解，