3168 - Comparision of Microcolumn Gel Assay and Tube Test for Identification of Anti-D Antibody among RH Negative Pregnant Women in Nepal

Abstract

Introduction: Pregnant women with a Rh-negative blood group may form Rh-antibodies if fetus has a Rh-positive blood. This sensitisation is likely to occur during birth, but can also happen in late pregnancy. These antibodies can cause anaemia or even death for future babies with RH positive blood from the mother. In pregnant women who are known to be RhD alloimmunized or for whom the prenatal antibody result is positive,anti-D concentration measurement is necessary,both to assess the risk to the fetus and to guide clinical decision-making. Methods: The study was conducted in the lab of Central blood transfusion centre from February to July 2015. During this period a total of 114 samples of RH negative women were processed. Anti-D antibody identification and titration is done by using indirect antiglobulin test by Conventional tube method using indirect antiglobulin technique in normal saline. Then parallel identification was done by Microcolumn gel assay, recommended by AABB manual using indirect antiglobulin technique in LISS (Low Ionic Strength Saline) solution. Results: Among a total of 114 pregnant women with RH negative blood processed during the study period, more than one-third (36%) were of blood group O, one-quarter were blood group A (25%), followed by blood group B (23%) and blood group AB (16%). Patients with blood group O showed the highest proportion of anti-D antibody positive cases (17%) . No case of anti-D antibody was detected among women with blood group AB. Among 114 pregnant women, 13 (11.04%) sample from Rh negative pregnant women were positive for anti D antibody. When comparing the titration approaches, the microcolumn gel assay showed more frequent significant titer value (1:1024) than that of tube method titration value. Among 13 samples positive for anti D antibody, gel method could identify positive for all 13 cases while Tube method showed positive anti D antibody in 12 cases only. Moreover, titre value shown by gel method was higher than that of tube method in all cases. Conclusion: The proportion of anti-D antibody positive cases are still higher in Nepal. Early detection and prevention is required to prevent hemolytic disease of Newborn. To identify anti D antibody, microcolumn gel assay is sensitive than tube method and can be a best alternative to tube method in our setting.