Perinatology, Amrita Institute of Medical Sciences and Research Centre, Amrita Vishwa Vidyapeetham University, Cochin, Kerala, India.
Transfusion Medicine, Amrita Institute of Medical Sciences and Research Centre, Amrita Vishwa Vidyapeetham University, Cochin, Kerala, India.
Transfus Apher Sci. 2020 Jun;59(3):102732. doi: 10.1016/j.transci.2020.102732. Epub 2020 Jan 31.
A critical anti D antibody titre, defined for the conventional tube method of Indirect Coomb's test (ICT), when employed in the more sensitive column method could result in unnecessary referrals and frequent obstetric doppler scans. This study aimed to compare anti D titres by tube and column method in antenatal mothers, to assess their correlation with fetal anemia and to determine a critical titre for the column method.
Forty six antenatal mothers with anti D antibody were included in the study. Antibody titration was performed by serial twofold dilution of serum by both column and tube method and were correlated with middle cerebral artery peak systolic velocity (MCA PSV) measurement by Doppler ultrasonography. Receiver operating curve (ROC) was used to determine the cut-offs for critical titre by tube and column method in predicting fetal anemia.
Column method had a median titre 3 fold higher than tube method. There was a significant association between fetal anemia by USG with median critical titres determined for both column (p = 0.031) and tube method (p = 0.016). ROC analysis showed the cut off for critical titres in column method as 64 with 90 % sensitivity, 72.7 % specificity and 75.38 % accuracy.
The use of critical titre for anti D antibody, defined for the tube method, when applied to the column agglutination method would lead to increased referrals to specialized fetal medicine centres. Rather, an Anti D titre of 64 by column method can predict the likelihood of fetal anemia and should be considered as the critical titre to guide patient referrals.
在间接 Coombs 试验（ICT）的常规试管法中，定义临界抗 D 抗体效价，如果在更敏感的柱法中使用，可能会导致不必要的转诊和频繁的产科多普勒扫描。本研究旨在比较产前母亲的试管法和柱法的抗 D 效价，评估其与胎儿贫血的相关性，并确定柱法的临界效价。
本研究纳入了 46 例抗 D 抗体阳性的产前母亲。采用试管法和柱法对血清进行连续两倍稀释，进行抗体滴定，并与多普勒超声测量大脑中动脉收缩期峰值流速（MCA PSV）相关联。使用受试者工作特征曲线（ROC）确定管法和柱法预测胎儿贫血的临界效价的截断值。
柱法的效价中位数比试管法高 3 倍。超声检查确定的胎儿贫血与柱法（p=0.031）和试管法（p=0.016）确定的临界效价中位数均有显著相关性。ROC 分析显示柱法的临界效价截断值为 64，灵敏度为 90%，特异性为 72.7%，准确性为 75.38%。
将试管法定义的临界抗 D 抗体效价应用于柱凝集法会导致更多的转诊到专门的胎儿医学中心。相反，柱法的抗 D 效价为 64 可以预测胎儿贫血的可能性，应被视为指导患者转诊的临界效价。
