Flocculation is the process by which serum antibodies come out of solution and precipitate; similiar to when making 'rock candy,' the sugar comes out of solution and latches on to the string.
Flocculation is a clear sign of an antibody reaction. Most of the flocculation I report results from avoids reacting with anti-blood type antibodies.
Most flocculation reactions are 'anomalous', in that they require the presence of a primary high-affinity, non-precipitating antibody (which may or may not be blood type specific; more usually bacterial-induced) that must be saturated with the food antigen before the remaining 'conventional' (blood type specific) antibodies bind and precipitate the additional antigen.
'Flocculate' is an old Greek word, meaning to produce white cloud-like tuffs in solution.
Often these antibody/antigen complexes (or 'Immune Complexes') activate other latent parts of the immune system, and which can result in inflammation and auto-immune disease. This is often done by stimulating the body's complement system.
Flocculates serum or precipitates serum http://web.indstate.edu/thcme/PSP/labtests/precip.htm
It makes the IgM antibodies found in your blood type clump up and come out of solution (precipitate)