Specimen Information

Type

Pink,EDTA

Volume

6.0mL

Transport Info

Refrigerated

Fasting Required?

False

Clinical Significance

The ABO system is the most important blood group system to be considered in transfusion therapy. The blood group is determined by the presence of the antigens A and/or B on the red cells that will agglutinate in the presence of antibodies directed toward the antigens. The strength of the antigens varies between individuals results
in the identification of subgroups. In addition, human serum normally contains a naturally occurring antibody directed against the A or B antigen that is lacking. The naturally occurring antibodies may be weak or absent in newborns, patients with low levels of serum globulins and in elderly people. ABO blood group is determined by a forward grouping using the individual's red cells and antiserum that contains a known antibody. In addition, a reverse grouping is performed using the individual's serum or plasma and red cells possessing a known antigen. Tests may be performed using a human source of anti-serum or with a monoclonal blend anti-serum. Because the D antigen is clinically significant and highly antigenic, the determination of its presence or absence in donor or recipient processing and in routine blood typing is essential. Reactivity of the D antigen may vary from one person to another. The reaction in vitro may be so weak that antiglobulin testing may be required in order to detect it. Cells that are positive only after antiglobulin testing are called Rh-positive, weak D (formerly referred to as Du variant).