Objectives: To investigate the interference of postmortem hemolysis on the detection of creatinine and whether ultrafiltration can reduce the interference.
Methods: A total of 33 non-hemolyzed whole blood samples from the left heart were collected. Hemolyzed samples with 4 hemoglobin mass concentration gradients H1-H4 were artificially prepared. Ultrafiltration was performed on each hemolyzed sample. Creatinine concentrations in non-hemolyzed serum (baseline serum), hemolyzed samples and ultrafiltrate were detected. Bias (B), Pearson correlation and receiver operator characteristic (ROC) of baseline creatinine concentration between before and after ultrafiltration were analyzed.
Results: As the hemoglobin mass concentration increased, B of the hemolyzed samples in the H1-H4 groups gradually increased, the |B| was 2.41(0.82, 8.25)-51.31(41.79, 188.25), reaching a maximum of 589.06%, and there was no statistically significant between the creatinine concentration and the baseline creatinine concentration (P=0.472 7, r=0.129 5). After ultrafiltration of hemolyzed samples, the interference of creatinine concentration in ultrafiltrate was significantly reduced, the |B| was 5.32(2.26, 9.22)-21.74(20.06, 25.58), reaching a maximum of 32.14%, and there was a positive correlation with baseline creatinine concentration (P<0.05, r=0.918 2). In the hemolyzed samples of H3 and H4 groups, there were 7 false-positive samples and 1 false-negative sample; in the ultrafiltrate samples, there were no false-positive sample and 1 false-negative sample. ROC analysis results showed the hemolyzed samples were lack of diagnostic value (P=0.117 5).
Conclusions: The postmortem hemolysis significantly interferes creatinine detection results of blood samples, ultrafiltration can reduce hemolysis-induced interference in postmortem creatinine detection.
目的: 探讨死后溶血对肌酐检测的干扰以及超滤处理是否可降低其干扰。方法: 收集33例未溶血左心全血样本，人工制备H1~H4 4个血红蛋白质量浓度梯度的溶血样本。对每例溶血样本进行超滤处理，检测未溶血血清（基线血清）、溶血样本及超滤液中的肌酐浓度，分析超滤前后与基线肌酐浓度间的偏倚（B）、Pearson相关性、受试者操作特征（receiver operator characteristic，ROC）。结果: 随着血红蛋白质量浓度的增高，H1~H4组溶血样本的偏倚逐渐增大［|B|为2.41（0.82，8.25）~51.31（41.79，188.25）］，最高为589.06%，肌酐浓度与基线肌酐浓度间无相关性（P=0.472 7，r=0.129 5）。溶血样本经超滤处理后，超滤液中的肌酐浓度所受干扰降低［|B|为5.32（2.26，9.22）~21.74（20.06，25.58）］，最高为32.14%，且与基线肌酐浓度间呈正相关（P<0.05，r=0.918 2）。H3和H4组溶血样本中出现7例假阳性样本、1例假阴性样本；超滤液中无假阳性样本，出现1例假阴性样本。ROC分析结果显示溶血样本缺乏诊断价值（P=0.117 5）。结论: 死后溶血严重干扰血液样本的肌酐检测结果，经超滤处理可以降低溶血对死后肌酐检测的干扰。.
Keywords: creatinine; forensic pathology; hemolysis; postmortem biochemical examination; ultrafiltration.