Center for Studies in Demography and Ecology, University of Washington, Seattle WA 98195, United States.
J Immunol Methods. 2010 Oct 31;362(1-2):112-20. doi: 10.1016/j.jim.2010.09.014. Epub 2010 Sep 17.
C-reactive protein (CRP) is used as a biomarker of morbidity and mortality risk in studies of population health, and is essential to interpretation of several micronutrient biomarkers. There is thus a need for a robust high-sensitivity CRP (hsCRP) measurement method for large-scale, non-clinical studies. We developed an efficient, inexpensive assay suitable for quantifying CRP across the physiological range using any blood specimen type. The ELISA uses readily available monoclonal antibodies to measure CRP in serum, plasma, or dried blood spots (DBS) made from venous or capillary blood. Assay performance was evaluated by standard methods, including comparison with a previously described assay. Effects of specimen type were tested by measuring CRP in 52 matched serum, plasma, and venous and capillary dried blood spot specimens. Long- and short-term CRP stability were evaluated. Assessments of assay limits of detection, linearity, recovery, imprecision, and concordance with an established method (Pearson correlation=0.988, n=20) demonstrated the validity of the new assay. CRP measurements in serum, plasma, and DBS had Pearson correlations from 0.974 to 0.995, n=52, but CRP in serum was on average 1.6 times (SD 0.37) higher than in DBS. CRP was stable in frozen serum for up to 34 months, but DBS CRP declined quickly with exposure to ambient temperatures, and across long-term storage at -20°C. This hsCRP assay is a robust and inexpensive tool designed for use in large-scale population health research. Our results indicate that DBS CRP is less stable than previously reported.
C-反应蛋白（CRP）被用作人群健康研究中发病率和死亡率风险的生物标志物，对几种微量营养素生物标志物的解释至关重要。因此，需要一种稳健的高灵敏度 C-反应蛋白（hsCRP）测量方法，用于大规模的非临床研究。我们开发了一种高效、廉价的测定法，适用于使用任何血液标本类型在生理范围内定量 CRP。该 ELISA 使用现成的单克隆抗体来测量血清、血浆或来自静脉或毛细血管血的干血斑（DBS）中的 CRP。通过标准方法评估了测定法的性能，包括与先前描述的测定法进行比较。通过测量 52 份匹配的血清、血浆和静脉及毛细血管干血斑标本中的 CRP 来测试标本类型的影响。评估了测定法的检测限、线性、回收率、精密度以及与既定方法的一致性（Pearson 相关系数=0.988，n=20）。CRP 在血清、血浆和 DBS 中的测量值的 Pearson 相关系数为 0.974 至 0.995，n=52，但血清中的 CRP 平均比 DBS 高 1.6 倍（SD 0.37）。冷冻血清中 CRP 最长可稳定 34 个月，但 DBS CRP 在暴露于环境温度时迅速下降，并在-20°C 下长期储存时也迅速下降。这种 hsCRP 测定法是一种稳健且廉价的工具，专为大规模人群健康研究而设计。我们的结果表明，DBS CRP 的稳定性不如先前报道的那样好。
