改良Bethesda方法、改良Nijmegen方法和空白法检测凝血因子Ⅷ抑制物及其影响因素

目的评价改良Bethesda方法、改良Nijmegen方法和空白法检测血友病A患者凝血因子Ⅷ抑制物的临床应用价值，并探 讨凝血因子Ⅷ抑制物检测的影响因素。方法采用改良Bethesda方法、改良Nijmegen方法和以去离子水替代缓冲液或乏Ⅷ因 子血浆的空白法，分别检测257例血友病A患者的抑制物水平，以抑制物滴度≥0.60 BU/mL判为阳性结果，并对3种方法检测结 果的阳性率及抑制物滴度水平进行分析。结果改良Bethesda 方法、改良Nijmegen 方法和空白法的阳性率分别为79.38%、 85.21%和72.37%。改良Bethesda方法与改良Nijmegen方法之间相关系数为0.996（P<0.001），两种方法的抑制物滴度水平之间 有显著的统计学差异（P<0.001），阳性率无显著的统计学差异（P=0.105）；改良Bethesda方法与空白法之间相关系数为0.994（P< 0.001），抑制物滴度水平之间有显著的统计学差异（P<0.001），阳性率无显著的统计学差异（P=0.079）；改良Nijmegen方法与空 白法之间相关系数为0.994（P<0.001），抑制物滴度水平之间有显著的统计学差异（P<0.001），阳性率有显著的统计学差异（P= 0.001）。结论改良Nijmegen方法具有较高的灵敏度，改良Bethesda方法次之，空白法最差。反应体系中各凝血因子活性水平 的一致性是影响凝血因子Ⅷ抑制物检测的主要因素，而稳定的缓冲体系也是影响检测结果稳定性、灵敏度及特异性不可忽视的 因素。

Modified Bethesda,modified Nijmegen and blank assays for coagulation factor VIII inhibitor detection and factors affecting the results

Objective To evaluate the clinical value of modified Bethesda assay, modified Nijmegen assay and blank assay for detection of coagulation factor VIII (FVIII) inhibitors in patients with hemophilia A and analyze the factors that affect FVIII inhibitor detection. Methods The levels of FVIII inhibitors in 257 patients with hemophilia A were detected using modified Bethesda assay, modified Nijmegen assay and blank assay (in which the buffer or FVIII-deficient plasma in the control mixture was replaced by deionized water). The 3 methods were compared for positivity rates and FVIII inhibitor titers based on the positive cut-off value of FVIII inhibitors ≥0.60 BU/mL. Results The positive rates of modified Bethesda assay, modified Nijmegen assay and blank assay were 79.38%, 85.21% and 72.37%, respectively. A strong correlation was found between the results by modified Bethesda assay and modified Nijmegen assay (r=0.996, P<0.001), and FVIII inhibitor titers (P<0.001) but not the positive rates (P=0.105) detected by the two methods differed significantly. The correlation coefficients between modified Nijmegen assay and blank assay was 0.994 (P<0.001), and a significant difference was found in FVIII inhibitor titers (P<0.001) but not the positivity rates (P=0.079) detected by the two methods. The correlation coefficient between modified Nijmegen assay and blank assay was 0.994 (r=0.994), and the two methods yielded significantly different FVIII inhibitor titers and positivity rates (P=0.001). Conclusion The modified Bethesda assay has a lower sensitivity than modified Nijmegen assay but has a higher sensitivity than blank assay. The consistency level of coagulation factors in the reaction system and stable buffer system are important factors that affect FVIII-inhibitor detection.