A class of immunoglobulin, a globulin protein of high molecular weight, which serves as an antibody.
A large protein molecule of the globulin series that is present in the blood and functions as an antibody, forming an effective first-line defense against bacteria in the bloodstream.
A globulin of high molecular weight over about 400,000. Macroglobulin is normally present in the blood but is increased in disease states such as multiple myeloma, connective tissue disease, cirrhosis of the liver, and amyloidosis.