Direct Antiglobulin Test

Polyspecific antihuman globulin (AHG) reagents are used for routine alloantibody detection, compatibility tests and the direct antiglobulin test (DAT). PolyspecificAHG contains antibody to human IgG and the C3d component of human complement, and may also react weakly with IgA and IgM molecules due to anti-light chain activity. A positive DAT generally indicates that the red cells are coated in vivo with immunoglobulin and/or complement. The most important function of the AHG reagent is to detect the presence of IgG-antibodies. The importance of anti-complement in the AHG reagent is debatable since antibodies detectable only by their ability to bind complement are rather rare. However, anti-C3d activity is important for the direct antiglobulin test in the investigation of autoimmune hemolytic anemia (AIHA).
Reference range: 


Sample type and Volume required: 
6ml K2EDTA
Call in advance: 
Turnaround time: 
4 hours
Time limit for extra tests: 
1 day
Blood Transfusion Laboratory at King's
Bessemer Wing
King's College Hospital
Bessemer Wing
Denmark Hill
London SE5 9RS
For clinical advice or interpretation of results, please contact the laboratory in the first instance.

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Last updated: 14/01/2021