To investigate the predictive effect of maternal immunoglobulin (Ig)G irregular antibody titer and titer score on blood exchange transfusion in rhesus maternal-fetal blood group incompatibility hemolytic disease of newborn (Rh-HDN).

From 2019 to 2021, 52 newborns who were diagnosed as Rh-HDN in the Blood Group Room of Jinan Blood Supply and Insurance Center were selected as research subjects. According to whether Rh-HDN newborns received blood exchange transfusion or not, they were divided into exchange transfusion group (n=28) and non-exchange transfusion group (n=24). Their red blood cell count (RBC), level of hemoglobin (Hb), hematocrit (HCT), serum total bilirubin (TBIL) concentration, ABO blood group and maternal IgG irregular antibody titer and titer score were detected, and were statistically compared by independent-samples t test or chi-square test. Receiver operating characteristic (ROC) curve of maternal IgG irregular antibody titer and titer score for predicting blood exchange transfusion of Rh-HDN newborns were drawn, and the area under the curve (AUC) was also calculated. The procedures followed in this study were in line with the requirements of Helsinki Declaration of the World Medical Association revised in 2013. There was no significant difference between two groups in terms of general clinical data, such as gender composition ratio (P>0.05).

①RBC, level of Hb, HCT in exchange transfusion group were significantly lower than those in non-exchange transfusion group, while serum TBIL concentration was significantly higher than that in non-exchange transfusion group, and all the differences were statistically significant (t=-7.94, -7.96, -8.80, 14.24; P<0.001). ②The maternal IgG irregular antibody titer and titer score in exchange transfusion group were significantly higher than those in non-exchange transfusion group, and the differences were statistically significant (Z=-4.91, t=8.72; P<0.001). ③There was statistically significant difference between maternal antibody titer and titer score for predicting blood exchange transfusion of Rh-HDN newborns (P=0.031). AUC of maternal antibody titer and titer score for predicting blood exchange transfusion of Rh-HDN newborns were 0.921 (95%CI: 0.853-0.990, P<0.001) and 0.958 (95%CI: 0.910-1.000, P<0.001), respectively, and the difference was statistically significant (Z=2.09, P=0.036). According to the principle of maximum Youden index, the optimal cut-off values for predicting blood exchange transfusion of Rh-HDN newborns by maternal IgG irregular antibody titer and titer score were 1∶80 and 57.5 points, respectively, and the sensitivities were 71.4% and 92.9%, specificities were 87.5% and 87.5%, positive predictive values were 87.0% and 89.7%, and negative predictive values were 72.4% and 91.3%, respectively.

Maternal IgG irregular antibody titer and titer score of Rh-HDN newborns have certain clinical value in predicting blood exchange transfusion of Rh-HDN newborns, and the predictive efficacy of maternal IgG irregular antibody titer score is better than that of maternal IgG irregular antibody titer.