Immunoassay for Immunoglobulin M (IgM) in Serum or Plasma

What Is Immunoglobulin M (IgM)?

IgM is a type of antibody produced primarily by the immune system in response to infections. It appears early in an infection and can help your body fight off pathogens like bacteria and viruses. Unlike other antibodies, IgM is often found in higher levels when your body is actively fighting an infection, especially if it’s new or the body is responding strongly.

When Might You Need This Test?

Your doctor may order an IgM test to check for recent infections, monitor immune responses, or investigate conditions like autoimmune diseases, chronic infections, or certain blood disorders. It’s also sometimes used in conjunction with other tests to help diagnose conditions such as hepatitis, Lyme disease, or other viral infections.

Common Uses in Healthcare

IgM testing is often used to detect acute infections, such as viral hepatitis (e.g., hepatitis A or B), Lyme disease, or other systemic infections. It can also help assess immune function in people with weakened immune systems or certain genetic disorders.

How Is This Test Performed?

A small blood sample is drawn from a vein in your arm. The blood is then processed to separate serum or plasma, which is tested for IgM levels using an immunoassay method. This method detects the presence and amount of IgM antibodies in your blood.