Background: A serology testing for infectious diseases (HIV, hepatitis B and C, syphilis) is mandatory in tissue donors. In many donors postmortem blood is the only sample available. Even though serological tests and nucleic acid amplification tests (NAT) used are validated for postmortem blood, a characterization of those blood samples is not yet established. We therefore investigated the total immunoglobulin G (IgG) content in postmortem blood of tissue donors and compared it to a corresponding antemortem blood sample. Methods: Ante- and postmortem blood samples were obtained from 100 consecutive tissue donors. The total IgG of all samples was measured using an immune-turbidometric test on the AU 480 Chemistry Analyzer (Beckman Coulter). Results: The mean total IgG concentration of antemortem blood samples from all 100 donors was 8.9 g/L ± 3.7 g/L (median 8.9 g/L, range 1.5 to 23.8 g/L). In 80 donors the IgG concentration in the antemortem blood sample was within the normal range with values ≥6 g/L (mean 10.0 g/L ± 3.3 g/L, median 9.3 g/L,). The total IgG concentration of the postmortem blood samples was lower with 7.2 g/L ± 3.2 g/L (median 6.7 g/L, range 0.6 to 18.2 g/L). The difference between the values of the antemortem and postmortem blood samples was 1.7 g/L ± 2.6 g/L (16.3%) (median 1.6 g/L, range –7.7 to 10.1 g/L). In 36 donors this difference was less than 10%, in 23 it was between 10 and 25%, in 33 between 26 and 50%, and in 8 over 50%. In 57 donors the total IgG in the postmortem blood sample was within the normal range with ≥6 g/L, in 53 of them also the value of the antemortem blood sample was within the normal range. No correlation for total IgG was found regarding the donor characteristics (age, sex, disease) and the sample characteristics (hemolysis, postmortem time). Conclusion: Total IgG values in antemortem samples were below the lower limit of 6 g/L in 20% of the cases. Total IgG was significantly lower in the postmortem samples compared to the antemortem samples, while 57% were still above the lower limit. No correlation with the postmortem time could be found. This lowered IgG levels should be payed attention to when using postmortem blood for infectious serology testing. Additional NAT testing should be considered.
Transfus Med Hemother

中文翻译：

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组织捐献者死前和死后血样中总免疫球蛋白 G 的比较

背景：组织捐赠者必须进行传染病（HIV、乙型和丙型肝炎、梅毒）的血清学检测。在许多捐献者中，死后血液是唯一可用的样本。尽管使用的血清学测试和核酸扩增测试 (NAT) 已被验证用于死后血液，但尚未确定这些血液样本的特征。因此，我们研究了组织捐献者死后血液中的总免疫球蛋白 G (IgG) 含量，并将其与相应的死前血液样本进行了比较。方法：从 100 个连续的组织捐赠者处获得死前和死后血样。使用 AU 480 化学分析仪 (Beckman Coulter) 上的免疫比浊测试测量所有样品的总 IgG。结果：来自所有 100 名献血者的生前血液样本的平均总 IgG 浓度为 8.9 g/L ± 3.7 g/L（中位数为 8.9 g/L，范围为 1.5 至 23.8 g/L）。在 80 名献血者中，生前血样中的 IgG 浓度在正常范围内，值≥6 g/L（平均 10.0 g/L ± 3.3 g/L，中位数 9.3 g/L）。死后血液样本的总 IgG 浓度较低，为 7.2 g/L ± 3.2 g/L（中位数 6.7 g/L，范围 0.6 至 18.2 g/L）。死前和死后血样值之间的差异为 1.7 g/L ± 2.6 g/L (16.3%)（中位数 1.6 g/L，范围 –7.7 至 10.1 g/L）。在 36 个供体中，这种差异小于 10%，在 23 个中介于 10% 和 25% 之间，在 33 个中介于 26% 和 50% 之间，在 8 个中超过 50%。在 57 名献血者中，死后血样中的总 IgG 在正常范围内，≥6 g/L，其中53人的生前血样值也在正常范围内。在供体特征（年龄、性别、疾病）和样本特征（溶血、死后时间）方面未发现总 IgG 的相关性。结论： 20%的病例生前样本中总IgG值低于6 g/L的下限。与死前样本相比，死后样本中的总 IgG 显着降低，而 57% 仍高于下限。没有发现与死后时间的相关性。在使用死后血液进行感染性血清学检测时，应注意这种降低的 IgG 水平。应考虑进行额外的 NAT 测试。
Transfus Med Hemother