Immunoglobulins (Ig) are critical components of the immune system and play a major role in eliciting the body's immune response against pathogens. Five heavy-chain isotypes (IgA, IgD, IgE, IgG, and IgM) mediate specific biological functions, including responses to pathogens and immunological diseases such as allergies and autoimmune disorders. IgM is a pentamer that comprises approximately 10% of serum immunoglobulin content. IgM level is often increased in samples associated with infectious diseases including primary biliary cirrhosis, infectious mononucleosis, cytomegalovirus infection, and tuberculosis. This kit provides the assay-specific components for the quantitative determination of IgM in human, cynomolgus monkey, and rhesus monkey samples.