Type and Screen Method versus Antihuman Globulin Crossmatch in Pretransfusion Testing: A Cross-sectional Study

Abstract

Introduction: Blood transfusion remains the primary modality of treatment for many serious and common diseases. According to the International Society of Blood Transfusion (ISBT), there are about 349 blood group antigens, out of which only about 25-28 antigens are known to cause acute or delayed type of haemolytic transfusion reactions which could be prevented by Pretransfusion Testing (PTT). Regulated pretransfusion tests include ABO blood grouping, Rh typing, antibody detection, antibody identification and compatibility testing. The purpose of compatibility tests is to demonstrate invitro red cell antigen-antibody reaction. The Antihuman Globulin (AHG) crossmatch testing can assure ABO compatibility between donor and patient blood as well as detect most clinically significant antibodies. Type and Screen (T&S) is a procedure carried out as part of PTT in which the recipient’s blood sample is tested for ABO group, RhD T&S for unexpected antibodies. Aim: To compare T&S method of PTT with AHG crossmatch. Materials and Methods: This cross-sectional study was conducted in the department of Transfusion medicine at Government Royapettah Hospital, Chennai and The Tamil Nadu Dr. MGR Medical University, Chennai, Tamil Nadu, India from June 2012 to December 2013. T&S was performed on 1,040 recipients’ (510 males and 530 females) samples. All these samples were subjected to AHG crossmatch with ABO group and RhD type matched donor samples to assess the compatibility between donor and recipient by using column agglutination technology. Statistical analysis was carried out using Statistical Package for the Social Sciences (SPSS) version 11.0. Results: The prevalence of unexpected antibodies in the recipient population was 1.06%. Among the 1,040 recipients’ blood samples, 11 samples were found to have unexpected antibodies. Out of these 11 samples, 10 showed exact antibodies and the remaining one sample with negative antibody screening was found to be incompatible with AHG crossmatch. The sensitivity and specificity of T&S method in comparison to AHG crossmatch was 87.50% and 99.71%, respectively. Conclusion: The sensitivity and specificity of T&S is as acceptable as AHG crossmatch. However, in view of one sample with false negative antibody screening in the study population, it is imperative to know the phenotyping of Red Blood Cells (RBC) antigens of the native population before getting away with AHG crossmatch.

Keywords

• antibody screening
• clinically significant antibodies
• international society of blood transfusion