Immunology
Immunoglobulin M
The first antibody class the body produces when it meets something new.
Unit mg/dLTypical adult range 50–300 mg/dL
What it is
The first antibody class the body produces when it meets something new.
Why it matters
Because it appears early and fades, a raised IgM points at a recent or current infection rather than an old one.
Reading the number
It is the antibody that says recent, where IgG says previous. A persistently raised value with no infection to explain it is a different kind of finding and one worth following up.
What moves it
recent infectionautoimmune conditionsliver disease
Read alongside
When to raise it
Worth discussing a raised value that persists once you are well.
Also known as
On a report in another language.
A lab report names this analyte in its own language. Vitals Vault recognises each of these and files them all under Immunoglobulin M.
Imunoglobulina M SéricaImunoglobulina MIgMImmunglobulin M
Catalog entry last updated 2026-08-28. Browse all 165 metrics.