Explanation

Parietal cell antibodies: what is measured?

Parietal cells are located in the stomach lining. They make stomach acid and intrinsic factor, the protein needed to absorb vitamin B12 from food. This test checks whether there are antibodies against those cells in the blood. If there are, the cells can be destroyed, a lasting inflammation of the stomach lining develops and, over time, a vitamin B12 deficiency can develop.

What can it detect?

Support when autoimmune gastritis is suspected, a lasting inflammation of the stomach lining caused by the body's own immune system
A clue to the cause of a vitamin B12 deficiency and of anemia with red blood cells that are too large (pernicious anemia)

Result

What does the result mean?

Positive result

A positive result means that antibodies against parietal cells were found. This may fit autoimmune gastritis, but according to the Dutch Society for Clinical Chemistry (NVKC), this antibody is not specific for it: it is also found in people with other autoimmune diseases and in healthy people, more often as people get older. A positive result on its own therefore does not mean that you have a stomach condition or a vitamin B12 deficiency. With symptoms such as tiredness, tingling in the hands or feet, a smooth tongue or stomach complaints, the result is assessed together with the blood count and the vitamin B12 level. Antibodies against intrinsic factor are less common but point much more strongly to pernicious anemia.

Negative result

A negative result means that no antibodies against parietal cells were found. Autoimmune gastritis is then less likely, but not ruled out: the antibodies can disappear as the disease progresses. A vitamin B12 deficiency can also have completely different causes, such as eating few animal products, a bowel condition, stomach surgery or long-term use of stomach acid inhibitors or metformin.

After an abnormal result

With a positive result, the GP usually has the blood count and the vitamin B12 level measured, sometimes together with antibodies against intrinsic factor. If a deficiency is confirmed, treatment with vitamin B12 follows, and sometimes a referral for an examination of the stomach with a scope. With a positive result without a deficiency and without symptoms, usually no treatment follows.

Reliability

How reliable is the test?

This test belongs with a specific question, usually a confirmed vitamin B12 deficiency or anemia with red blood cells that are too large. The antibody is sensitive but not very specific: it also occurs in healthy people and in other autoimmune diseases, so a positive result without symptoms or without an abnormal blood count says little. In people without symptoms, the chance of a false-positive result is therefore greater than the chance that there really is a stomach condition. The result can only be interpreted together with the blood count and the vitamin B12 level.

What can affect the result?

These antibodies also occur in healthy people and in other autoimmune diseases, such as thyroid disorders and type 1 diabetes, and more often at an older age.
The antibodies can disappear as the disease progresses; a negative result therefore does not rule out autoimmune gastritis.
The test says nothing about how high or low the vitamin B12 in the blood is; a separate test is needed for that.
Laboratories use different methods and cut-off values; results cannot simply be compared.

Who it is for

Who is the test useful for?

Useful for

Useful if a vitamin B12 deficiency or anemia with red blood cells that are too large has already been confirmed and the cause is still unclear, or with long-lasting stomach complaints where autoimmune gastritis is being considered. In people without symptoms and with a normal blood count, a positive result says little, because these antibodies also occur without disease.

How common is it?

Autoimmune gastritis is not rare at an older age, but by no means always causes symptoms. Antibodies against parietal cells are also found in people without stomach complaints, and more often as people get older. Pernicious anemia, the form of anemia it can cause, is one of the known causes of a vitamin B12 deficiency.

NVKC, allesovertesten.nl and the NHG guideline on anemia; no Dutch prevalence figure has been checked

Drawbacks and risks

A positive result without symptoms and with a normal blood count is fairly common and can lead to unnecessary worry and to a stomach examination that was not needed.
A negative result does not rule out a vitamin B12 deficiency or autoimmune gastritis and can therefore give false reassurance.

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