What it measures
The total amount of IgM antibodies in the blood. IgM is the first antibody class the body makes against a new infection. It is a large antibody that stays mostly in the bloodstream.
Why people test it
- Investigating frequent infections, usually together with IgG and IgA.
- Measured when another blood test suggests myeloma or a related condition that makes IgM.
- Checking IgM in some liver conditions, where it can be raised.
Typical range
Gloucestershire Hospitals' laboratory gives an adult range (ages 16 to 60) of 0.40 to 2.30 g/L. Ranges vary by lab, method, age and sex, and your report shows the lab's own range. Source: Gloucestershire Hospitals NHS Foundation Trust, Pathology: Immunoglobulins and electrophoresis.
Finger-prick or vein?
A finger-prick sample is usually fine for this test, and some providers offer a home kit. Others take blood from a vein at a clinic.