Low-incidence antigens are antigens that occur in less than 1% of the population.
Antibodies to low-incidence antigens
Low-incidence antigens are not usually found on screen cell and antibody panels.
Antibodies are hard to test for, but it is usually not difficult to find compatible blood.
Suspect this antibody if an AHG crossmatch is incompatible and other causes have been ruled out, such as a positive donor DAT or ABO incompatibility.
Examples of low-incidence antigens include: Cw, V, Kpa, Jsa.
When going through the process of Ruling Out, antibodies like anti-V, anti-Cw, anti-Lua, anti-Kpa, and anti-Jsa usually fall into the "unable to rule out" category.
High-incidence antigens are antigens that occur in greater than 99% of the population.
Antibodies to high-incidence antigens
- Antibodies are rare and may be difficult to identify due to lack of negative panel cells for other high-incidence antigens (difficult to rule out).
- Reactions with screen and panel cells will all be positive (same strength and same phase).
- Auto control will be negative.
- Difficult to find antigen-negative compatible blood.
- Examples of antibodies to high-incidence antigens are: anti-k, anti-Kpb, anti-Jsb, and anti-Lub.
If an antibody to either a high- or low-incidence antigen is present, it may be difficult to identify and may require further testing in a reference blood bank.