IgM (immunoglobulin M) is the first antibody produced by the immune system in response to a new infection. It is the largest antibody and is found mainly in the blood.
Category: Inflammation & Immune
Also known as: igm, immunoglobulin m, serum igm
Reference range: 40–230 mg/dL (Source: ABIM)
Standard unit: mg/dL
High values may indicate
High IgM levels may indicate an acute or recent infection, Waldenstrom's macroglobulinemia (lymphoplasmacytic lymphoma), primary biliary cholangitis, or hyper-IgM syndrome.
Low values may indicate
Low IgM levels may indicate immunodeficiency disorders, multiple myeloma (non-IgM type), or conditions causing protein loss, and may increase susceptibility to infections.