Understand Your LABs

Understanding the difference between compatibility testing and crossmatching , and when/why both are needed, is essential in transfusion medicine. Let's break it all down clearly: 1. Compatibility Testing  Compatibility Testing is a broad term that refers to all the procedures used to ensure that the donor’s blood and the recipient’s blood are compatible for transfusion. This testing is crucial to prevent adverse transfusion reactions, which can be life-threatening.  Components of Compatibility Testing - Blood Grouping (ABO and Rh typing): Determining the blood group of both donor and recipient to ensure compatibility. - Antibody Screening: Detecting unexpected alloantibodies in the recipient’s serum that might react with donor RBCs. - Crossmatching (a part of Compatibility Testing, explained below). - Other tests: Sometimes additional tests like direct antiglobulin test (DAT) are performed to check sensitization. 2. Crossmatch Testing  Crossmatch is a specific laborato...

 The term "antithetical antigen" typically refers to a pair of antigens that are encoded by different alleles at the same genetic locus and are mutually exclusive  meaning, if one is present on a red blood cell, the other cannot be. This concept is most commonly used in immunohematology , especially in blood group systems like the Kell, Duffy, Kidd, MNS, and Rh systems . Table of Contents Introduction Defining Antithetical Antigens in Blood Group Systems Genetic Basis of Antithetical Antigens Examples of Antithetical Antigens in Specific Blood Group Systems Clinical Relevance of Antithetical Antigens Role of ISBT and Nomenclature Updates in Blood Group Terminology Visualization and Data Comparisons Conclusion 1. Introduction Blood transfusion and immunohematology require precise identification and classification of blood group antigens. Among these antigens, the concept of antithetical pairs is not only fundamental in understanding red cell immunogenetics but al...