Pre-Transfusion Serological Testing: Are we Doing it Right?

Abstract

Pre-transfusion testing is performed to ensure the normal survival of transfused red blood cell products i.e. to prevent hemolytic transfusion reaction via immune-mediated mechanism.1 The serological part of pre-transfusion testing includes; ABO group and Rh (D) type, antibody screening and crossmatching.2 Antibody screening is included to detect unexpected antibody and was first introduced after the discovery of Coombs test “antiglobulin test” in 1945.3 With the characterization of more red blood cell antibodies, more tests and different techniques were introduced. The main goal of antibody screening test is to maximize the detection of so called clinically significant antibodies and in the same content to minimize the detection of clinically insignificant antibodies.4 In order to meet this general aim many tests and techniques were initiated the first of which was the indirect antiglobulin test (IAT).3 Antiglobulin sera (AHG) may have different specificities; monospecific AHG sera such as anti-IgG and anti-C3d or polyspecific that contain both anti-IgG and anti-C3d.5,6 Furthermore, in order to decrease the testing time and/or to increase the sensitivity of the testing outcome, many enhancement media have been described to be used in conjunction with the IAT.3 An example of the additives is albumin that helps reduce repulsive forces between red blood cells.7 Another example is that of low ionic strength solution (LISS) which reduces the ionic strength accelerating antibody binding to red cells.8 In addition includes polyethylene glycol (PEG), which is a water-soluble linear polymer that potentiates antigen-antibody reactions.9