Chromogranin A: what it is, what it tells you and when it’s tested

Chromogranin A is a protein made by neuroendocrine cells, which are spread through many organs, for example the gut, pancreas and lungs. Some tumours of these cells, called neuroendocrine tumours, make more of it. But among the most common causes of a high value are medicines for stomach acid. It is not used to look for cancer in people who feel well.

When it’s tested

It is ordered by a specialist, usually an endocrinologist or oncologist, when they suspect a neuroendocrine tumour or to follow someone who has one. It is sometimes used in the follow-up of medullary thyroid cancer too.

It is not a screening test. Guidelines advise against using it to look for a tumour in people with common digestive complaints: it often rises for other reasons, and neuroendocrine tumours are rare.

That is why Rosa does not test it. The Rosa panel is a general prevention check-up, not a cancer test: it looks at your heart, metabolism, liver, kidneys, thyroid and blood.

What it tells you, and what it does not

A high chromogranin A does not mean cancer. Stomach acid medicines, atrophic gastritis and kidneys that work less well are the most common causes of a high value without a tumour.

A normal chromogranin A does not rule out a neuroendocrine tumour: some do not raise it.

The value changes a lot with the lab’s method. To follow it over time, you need the same lab every time.

Your doctor reads it together with other tests:

Normal chromogranin A levels

Normal levels depend heavily on the method. Some labs give a limit of around 100 ng/mL, others use different units and limits. Only the range on your own report counts.

If you take a medicine for stomach acid, the value can be high, sometimes very high. Tell your doctor before the test.

Why chromogranin A can be high

Often the cause is not a tumour. The most common come first.

Chromogranin A and stomach medicines

This is the most frequent reason for a high value that means nothing serious. These medicines lower stomach acid, and the stomach responds by making more chromogranin A.

Once the medicine is stopped, the value falls slowly: it usually takes at least two weeks.

If your doctor orders chromogranin A and you take one of these medicines, tell them. They decide whether to pause it for a while before the blood test, and how. Do not stop it on your own.

If your chromogranin A is above the limit

Try not to worry: a high value often has benign causes. Where to start:

When to talk to a doctor

Talk to your doctor if:

Frequently asked questions

High chromogranin A: what are the causes? The most common are stomach acid medicines, atrophic gastritis and kidneys that work less well. More rarely, a neuroendocrine tumour.

Does pantoprazole raise chromogranin A? Yes. Pantoprazole, omeprazole and the other proton pump inhibitors raise it, sometimes by a lot. Tell your doctor before the test: they decide whether and how to pause them. Do not do it on your own.

What are normal chromogranin A levels? They depend heavily on the method. Some labs give a limit of around 100 ng/mL, others use different units and limits. Only the range on your own report counts.

Is chromogranin A a good test for prevention? No. It is not a test to have as a check-up, not even if you have common digestive complaints. It is used when a specialist suspects a neuroendocrine tumour, or to follow one.

Does Rosa test chromogranin A? No. Rosa is a general prevention check-up and does not include tumour markers. If your doctor thinks chromogranin A is useful, they order it separately.

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