When used by the recommended techniques, latex particles in the reagent will agglutinate (clump) in the presence of Toxoplasma gondii antibodies. No agglutination generally indicates absence of the Toxoplasma antibody

The Jka and Jkb antigens were reported in 1951 and 1953 respectively. Anti-Jka and anti-Jkb can both show dosage and are notorious for their evanescence: antibody titres that rise after stimulation but quickly drop, often to undetectable levels. Kidd system antibodies have been implicated in delayed and immediate Haemolytic Transfusion Reactions and Haemolytic Disease of the Newborn.

In 1945, Coombs, Mourant and Race described the use of anti-human globulin serum for detection of red cell-bound non-agglutinating antibodies and the antiglobulin (Coombs) test was rapidly applied. One cause of false negative antiglobulin tests is improper washing of the cells which results in free globulin molecules being present with supposedly washed cells and these globulins neutralise the antiglobulin serum when it is added. A negative result in an antiglobulin test should only occur when anti-human globulin is added to red cells that are not sensitised. To show that test cells were properly washed and that no neutralisation has occurred, antibody-coated cells are used as a positive indicator.

Levine and Stetson discovered the Rh blood group system in 1940. Apart from D the other major Rh antigens are C, E, c and e. The D antigen is highly immunogenic and the C and e antigens are less immunogenic than E and c. The Cw antigen is one of the more rare antigens, but Anti-Cw is a fairly commonly encountered antibody. All the Rh antibodies are clinically significant since they may cause both Transfusion Reactions and Haemolytic Disease of the Newborn.

The Fya and Fyb antigens were reported in 1950 and 1951 respectively. Anti-Fya and anti-Fyb have both been implicated in immediate and delayed Haemolytic Transfusion Reactions and Haemolytic Disease of the Newborn.