The short answer
Chromogranin A (CgA) is a tumor marker NCI lists for neuroendocrine tumors. Noncancerous conditions can also raise tumor markers. Care teams may measure it to help with diagnosis, check how treatment is working, or look for cancer coming back. It is read together with other results.
Chromogranin A (CgA) is a tumor marker measured in blood.
It is used as a tumor marker mainly with neuroendocrine tumors.
Noncancerous conditions can also raise tumor markers, and not everyone with a cancer has a high level.
It helps with diagnosis, treatment follow-up, and checking for recurrence, alongside other tests.
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The short version
Chromogranin A, often written CgA, is a tumor marker NCI lists for tumors that start in neuroendocrine cells. CgA is used as a tumor marker: a substance that can run higher in some cancers. It is not a simple yes-or-no cancer test.
What CgA is used for
NCI lists CgA as a marker for neuroendocrine tumors. Measuring it may help to:
- Support a diagnosis, together with other tests.
- Find out how well treatment is working.
- Check whether cancer has come back.
Why it is not read alone
NCI says noncancerous conditions can sometimes raise tumor markers, and not everyone with a given cancer has a higher level. So your care team reads CgA together with scans and other results. When CgA is checked again and again, the pattern over time can help show whether treatment is working.
Normal ranges vary by lab
Your report lists a reference range, the range that lab calls normal. Labs often use different testing methods, so they often use different ranges. That means results from different labs can't always be compared directly. Your care team knows which lab ran your test and how to read your result.
What to ask
Ask why your care team is measuring CgA. Ask what your level and its trend suggest, and whether anything else could affect it. Their reading of your full picture is what applies to you.
Sources
Common questions
Does a high chromogranin A mean I have cancer?
Not by itself. NCI lists CgA as a marker for neuroendocrine tumors. NCI also says noncancerous conditions can raise tumor markers, and not everyone with a given cancer has a higher level. Your care team reads CgA in context.
What is a neuroendocrine tumor?
It is a tumor that starts in neuroendocrine cells. Ask your care team what type you have and how CgA is used for it.
Why is CgA checked more than once?
NCI says repeated measurements during treatment can show whether a tumor is responding, and NCI lists CgA as a way to check whether cancer has come back. Ask your care team how to read your trend.
Can other things affect my CgA result?
Yes. NCI says noncancerous conditions can sometimes raise tumor markers. Ask your care team whether anything else could affect your result and whether you need to prepare for the test.
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Sources last checked: 2026-10-02 what this meansLast updated: 2026-10-02Next planned review: 2027-09-27
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Cancer Explained does not originate medical claims. Every page restates guidance already published by the National Cancer Institute, the CDC, the USPSTF and the FDA, in plain language, with the source cited so you can check the original yourself. AI does the translating and organizing; automated checks test claims, citations, clarity and safety before anything publishes, and this is translation and navigation, not clinical judgment. Nothing here is personal medical advice, and no page can account for your particular situation.
Editorial status: Source checked — This page was written with AI assistance and then compared with the sources listed on it, looking for statements those sources do not back up. That check is not a sentence-by-sentence record and can miss errors. It is not a medical review, and it does not confirm the page is complete or right for your situation.
Human medical review: not completed. Pages here are not signed off by a clinician before they publish. That is not an oversight we are quietly working around: we restate published guidance and cite it, so the authority belongs to the source rather than to us, and every page names where its claims come from — you can verify us instead of trusting us. Where a volunteer clinician has reviewed a page, their name and credentials appear on it; where no name appears, no clinician has checked it. We are glad to have reviewers and are recruiting them, and we do not hold pages back waiting for one. Use this site to understand your situation and to ask better questions of the people treating you.
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