BACKGROUND The stability of biomarkers in stored biomedical samples is crucial, especially when storage is for extended periods of time. High-sensitivity CRP (Hs-CRP) is a biomarker of low grade inflammation that is extensively used to identify and study cardiovascular and/or inflammatory processes in clinical care and large epidemiologic studies. Therefore, assessing Hs-CRP stability in archived samples at a given temperature is important to ensure precision of measurements over time and the validity of studies using archived samples. METHODS We evaluated the stability of Hs-CRP in 30 randomly selected human serum samples by measuring Hs-CRP concentrations in freshly collected sample [Hs-CRP (0)] and in the same set of samples after 7-11years of storage at -80°C [Hs-CRP (LT)]. RESULTS Hs-CRP did not significantly change up to 11years of storage at -80°C as shown by a negligible median difference between Hs-CRP (0) and Hs-CRP (LT), delta(Hs-CRP (0)-Hs-CRP (LT))=-0.01, p=0.45. There was a good concordance and agreement between Hs-CRP (0) and Hs-CRP (LT) as measured respectively by Lin's coefficient of correlation (ρC=0.98) and Bland-Altman analysis (mean difference=-0.02, 95% CI [-0.04-0.0045] p=0.107). In addition, the data also suggest that the time elapsed between collection and Hs-CRP measurement does not affect Hs-CRP stability over time when samples are kept under the appropriate conditions. CONCLUSIONS Long-term storage at -80°C for up to 11years did not significantly affect the stability of serum Hs-CRP. Given the cost and time for collecting fresh samples, this observation represents an important finding for biomedical research and clinical care.

中文翻译：

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高灵敏度 C 反应蛋白 (Hs-CRP) 在长期存档的人血清中保持高度稳定。

背景生物医学样品中生物标志物的稳定性至关重要，特别是当储存时间较长时。高敏 CRP (Hs-CRP) 是一种低度炎症的生物标志物，广泛用于在临床护理和大型流行病学研究中识别和研究心血管和/或炎症过程。因此，在给定温度下评估存档样品中 Hs-CRP 的稳定性对于确保随时间推移的测量精度和使用存档样品的研究的有效性非常重要。方法 我们通过测量新鲜采集的样品 [Hs-CRP (0)] 和同一组样品中的 Hs-CRP 浓度来评估 Hs-CRP 在 30 个随机选择的人血清样品中的稳定性，该浓度在 -80 ℃下储存 7-11 年。 °C [Hs-CRP (LT)]。结果 Hs-CRP 在 -80°C 下储存长达 11 年没有显着变化，如 Hs-CRP (0) 和 Hs-CRP (LT)、delta(Hs-CRP (0)-Hs 之间的中值差异可忽略不计） -CRP (LT))=-0.01，p=0.45。分别通过 Lin 相关系数 (ρC=0.98) 和 Bland-Altman 分析（平均差=-0.02，95% CI [ -0.04-0.0045] p=0.107）。此外，数据还表明，当样本保持在适当的条件下时，收集和 Hs-CRP 测量之间经过的时间不会影响 Hs-CRP 随时间的稳定性。结论 -80°C 下长期保存长达 11 年对血清 Hs-CRP 的稳定性没有显着影响。考虑到收集新鲜样品的成本和时间，