What is the cryoglobulin blood test?

Seeks odd proteins. This is a simple test for certain abnormal proteins in the bloodstream. Often they are rheumatoid facators, hepatitis C antigen-antibody complexes, or hepatitis B complexes. Plasma / serum is drawn and spun in the warm, then cooled and a white precipitate is a cryoglobulin. These can make you quite sick and should be sought especially if vasculitis or glomerulonephritis are sought.