Articles on Medical Diseases and Conditions

Entries for the ‘Immunohematology’ Category

White Blood Cell Antigens

The RBC ABO surface antigens are found in most tissues except the central nervous system (CNS). Some of the other RBC antigens, such as the P system, may occur in some locations outside the RBCs. White blood cells also possess a complex antigen group that is found in other tissues; more specifically, in nucleated cells. […]

Type and Screen

Current recommended procedure for pretransfusion testing, as previously described, is to obtain the ABO and Rh type of the recipient RBCs and perform an antibody screen on the serum of the recipient. This has become known as type and screen. This is followed by a crossmatch on blood units actually transfused; only the immediate spin […]

Pretransfusion Test Considerations

A word must also be said regarding a few patients whose blood presents unexplained difficulty in crossmatching. The laboratory should be allowed to solve the problem and possibly to obtain aid from a reference laboratory. During this time 5% serum albumin or saline may temporarily assist the patient. In the absence of complete crossmatching, blood […]

Major Crossmatch

From approximately 1960 to 1984, the purpose of the major crossmatch was to detect unexpected antibodies in the serum of the recipient, and it also acted as a check on a previous antibody screen. It also served as a check on ABO typing, since a mistake in ABO typing may result in RBCs from the […]

Antibody Screen

Even if major blood group typing has been done, transfusion reactions can occur due to unexpected antibodies in the serum of the recipient or due to incorrect RBC typing. To prevent reactions, the concept of a crossmatch evolved. The basic procedure is the “major” crossmatch, in which RBCs of the donor are placed into the […]

Other Blood Group Antigen Systems

Besides the ABO and the Rh system there are a number of other unrelated blood group antigen systems that have some importance, either for medicolegal parenthood studies or because sensitization to these antigens causes transfusion reactions or hemolytic disease of the newborn. The most important of these systemsis Kell (K), a well-recognized blood bank problem. […]

Rh Blood Group System

The next major blood group is the Rh system. There is considerable controversy over nomenclature of the Rh genetic apparatus between advocates of the English Fisher-Race CDE-cde nomenclature and the American Wiener’s Rh-hr labeling (Fig. 9-1) Fig. 9-1 Comparison of the Fisher-Race and Wiener nomenclatures. (From Hyland reference manual of immunohematology, ed 2. Los Angeles, […]

ABO Blood Group System

The ABO blood group system is a classic example of agglutinogens and their corresponding isoantibodies. There are three of these antigens—A, B, and O—whose genes are placed in one locus on each of two paired chromosomes. These genes are alleles, meaning that they are interchangeable at their chromosome location. Therefore, each of the paired chromosomes […]


Autoantibodies present an interesting problem, both in their clinical manifestations and in the difficulty of laboratory detection and identification. They may be either the warm or cold type and may be complete or incomplete. Warm autoantibodies react at body temperature and are most often of the incomplete type. They comprise about 70% of autoantibodies. They […]

Antibody Detection Methods

There are two methods of detecting and characterizing antibodies: (1) the direct Coombs’ test and (2) a group of procedures that try to determine if an antibody is present, and if present, attempt to identify the antibody by showing what the antibody will do in various controlled conditions. Direct Coombs’ test To prepare reagents for […]