All tests › Inflammation and immune system

Anticardiolipin IgM

Inflammation and immune system · also printed as Anticardiolipin IgM, aCL IgM, Cardiolipin IgM, Anti-cardiolipin IgM, ACA IgM

Typical UK adult rangebelow 20 U/mL

Below the lab's threshold, often 20 units, is the usual result; moderate and high bands are printed above 40.

What this test measures

Anticardiolipin IgM is the other class of the same antibody; it is less strongly linked with clotting than IgG. A positive needs confirming on a second sample twelve weeks later, because infections cause short-lived positives.

Why doctors request it

Requested after unexplained clots, in recurrent miscarriage clinics and in lupus.

What commonly pushes it up

Antiphospholipid syndrome
Lupus
Infections, giving a temporary positive
Some medicines as a class

What commonly pushes it down

A negative result is the usual finding

Everyday reasons for a value outside the range

Temporary positives after infections are common, which is why the test is repeated after twelve weeks
Units (GPL, MPL, U/mL) and thresholds differ between labs

About the sample

No fasting needed. Repeated after twelve weeks if positive.

Written by a UK consultant physician. Typical UK adult reference ranges; your laboratory's own printed range takes precedence.

Got a report with Anticardiolipin IgM on it?

Upload a photo or PDF and see every line against the range your lab printed, explained in plain English. First report free.

Read my report free

This is an educational summary of results you uploaded. It is not medical advice, a diagnosis or a treatment plan, and it does not replace the doctor who requested the test. If you are worried, or a result is marked outside range, discuss it with your doctor. Written and reviewed by a UK consultant physician. Reference ranges vary between laboratories.