Blood draw
Immunoglobulin: IgA, IgG, and IgM
Total IgA, IgG, and IgM; broad immunity assessment.
€ 68,00
All tests
Inflammation and immunity · Blood
IgM (immunoglobulin M)
The amount of IgM antibodies, the type the body makes first in a new infection.
At a glance
- Measured in blood
- In 2 test panels
- No special preparation
Explanation
IgM (immunoglobulin M): what is measured?
Immunoglobulins are antibodies that white blood cells make against bacteria, viruses and other invaders. IgM is the type the body makes first in a new infection; after that, IgG takes over this task. The test measures the total amount of IgM in the blood and so does not say which infection you have or have had.
What can it detect?
- A recent or ongoing infection (raised value)
- Long-lasting inflammations, autoimmune diseases and liver diseases (raised value)
- A shortage of antibodies, usually together with a low IgG or IgA
- Rarely: a condition in which one group of immune cells makes too much of one type of IgM (M-protein)
Result
What does the result mean?
IgM (immunoglobulin M) too high
A slightly raised IgM often fits a recent infection, because IgM rises first. Long-lasting inflammation, autoimmune diseases and liver diseases can also raise the value. The raised level itself causes no symptoms; those belong to the cause. Rarely, a strongly raised value means that one group of immune cells is making too much of one type of IgM (an M-protein); the laboratory looks into this further with protein electrophoresis.
IgM (immunoglobulin M) too low
A low IgM usually occurs together with a low IgG or IgA and then fits an immune disorder, in which you get more infections of the ears, sinuses or airways. In CVID, IgG and IgA are always low and IgM sometimes. Medicines that suppress the immune system and protein loss through the kidneys can also lower the value. A slightly low IgM without other abnormalities and without symptoms usually has little meaning.
After an abnormal result
With an abnormal value, the GP usually repeats the measurement together with IgA and IgG, preferably once any infection is over. With a lasting shortage and repeated infections, you are referred to an internist (specialist in internal medicine), immunologist or pediatrician. With a strongly raised value without an explanation, protein electrophoresis usually follows.
Reliability
How reliable is the test?
IgM can be measured accurately, but the value fluctuates with infections and says little on its own. According to the Dutch Society for Clinical Chemistry (NVKC), IgM is measured together with IgA and IgG in people who have frequent or repeated infections, or after a total protein that is too high has been found. A raised value can only be interpreted together with the other immunoglobulins, the symptoms and, if needed, protein electrophoresis.
What can affect the result?
- Reference values depend on age and differ by laboratory.
- A recent infection temporarily raises IgM; a measurement shortly after an infection is therefore hard to interpret.
- Medicines that suppress the immune system can lower the value.
- The result does not say which pathogen the antibodies are directed against.
Who it is for
Who is the test useful for?
Useful for
Useful with frequently recurring infections, together with IgA and IgG, and if a total protein that is too high was found earlier. For people without symptoms, a single IgM measurement yields little: the value varies with past infections and a slightly abnormal result is usually harmless.
How common is it?
A temporarily raised IgM due to an infection is common. A shortage of antibodies is rare: CVID, the most common inborn immune disorder, occurs in about 1 in 25,000 people. There are no Dutch figures on how often an abnormal IgM is found as an isolated finding.
Leven met een afweerstoornis (SAS) and NVKC (allesovertesten.nl)
Drawbacks and risks
- A slightly abnormal IgM without symptoms is often temporary and, without a repeat measurement, can cause unnecessary worry.
- A normal value does not rule out an immune disorder or an infection.
Evidence
Sources
This explanation is based on Dutch guidelines and independent information. It is general information, not a diagnosis. Discuss an abnormal result with your GP.
More about risks and resultsMore explanations
Other tests: Inflammation and immunity
- ACE
- Acetylcholine receptor antibodies
- ANA screening (antinuclear antibodies)
- Anti-CCP
- Antimitochondrial antibodies (AMA)
- Autoimmune hepatitis antibodies
- CRP
- ENA (antibodies against extractable nuclear antigens)
- Erythrocyte sedimentation rate
- hs-CRP
- IgA (immunoglobulin A)
- IgG (immunoglobulin G)