National Center for Clinical Laboratories, Beijing Engineering Research Center of Laboratory Medicine, Beijing Hospital, National Center of Gerontology, Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, China.
National Center for Clinical Laboratories, Beijing Engineering Research Center of Laboratory Medicine, Beijing Hospital, National Center of Gerontology, Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, China.
Ann Lab Med. 2023 Jul 1;43(4):345-354. doi: 10.3343/alm.2023.43.4.345. Epub 2023 Feb 24.
Serum C-peptide results from various routine methods used in China are highly variable, warranting well-performing methods to serve as an accuracy base to improve the harmonization of C-peptide measurements in China. We developed an accurate isotope dilution liquid chromatography-tandem mass spectrometry (ID-LC-MS/MS) method for serum C-peptide measurement and explored its use in harmonization.
After protein precipitation with ZSO solution, C-peptide was extracted from serum samples by anion-exchange solid-phase extraction and quantified by ID-LC-MS/MS in positive ion mode. The precision and analytical recovery of the ID-LC-MS/MS method were assessed. Seventy-six serum samples were analyzed using the ID-LC-MS/MS method and six routine immunoassays. Ordinary linear regression (OLR) and Bland-Altman (BA) analyses were conducted to evaluate the relationship between the ID-LC-MS/MS method and routine immunoassays. Five serum pool samples assigned using the ID-LC-MS/MS method were used to recalibrate the routine assays. OLR and BA analyses were re-conducted after recalibration.
The within-run, between-run, and total precision for the ID-LC-MS/MS method at four concentrations were 1.0%-2.1%, 0.6%-1.2%, and 1.3%-2.2%, respectively. The analytical recoveries for the ID-LC-MS/MS method at three concentrations were 100.3%-100.7%, 100.4%-101.0%, and 99.6%-100.7%. The developed method and the immunoassays were strongly correlated, with all R >0.98. The comparability among the immunoassays was substantially improved after recalibration.
The performance of the ID-LC-MS/MS method was carefully validated, and this method can be used to improve the harmonization of serum C-peptide measurements in China.
中国各常规方法检测血清 C 肽的结果差异较大，需要寻找性能优良的方法作为准确度基准，以提高中国 C 肽检测的一致性。本研究建立了一种准确的血清 C 肽同位素稀释液相色谱-串联质谱（ID-LC-MS/MS）检测方法，并对其在一致性方面的应用进行了探讨。
采用 ZSO 溶液沉淀蛋白后，用阴离子交换固相萃取法提取血清样本中的 C 肽，采用正离子模式的 ID-LC-MS/MS 定量。评估 ID-LC-MS/MS 方法的精密度和分析回收率。采用 ID-LC-MS/MS 方法和 6 种常规免疫分析法分析 76 份血清样本。采用普通线性回归（OLR）和 Bland-Altman（BA）分析评估 ID-LC-MS/MS 方法与常规免疫分析法之间的关系。使用 ID-LC-MS/MS 方法赋值的 5 个血清混合样本对常规方法进行重新校准，然后重新进行 OLR 和 BA 分析。
ID-LC-MS/MS 方法在 4 个浓度的批内、批间和总精密度分别为 1.0%-2.1%、0.6%-1.2%和 1.3%-2.2%，回收率分别为 100.3%-100.7%、100.4%-101.0%和 99.6%-100.7%。所建立的方法与免疫分析法均具有较强的相关性，所有 R 值均大于 0.98。经过重新校准，免疫分析法之间的可比性得到显著改善。
对 ID-LC-MS/MS 方法的性能进行了仔细验证，该方法可用于提高中国血清 C 肽检测的一致性。
