Chromogranin A
What this test measures
Chromogranin A is a protein stored in hormone-producing nerve-like cells throughout the body. Tumour markers are proteins that can rise for many reasons, most of them not cancer. Specialists mainly use them to follow a condition that has already been identified, and a single value cannot answer a screening question on its own.
Why doctors request it
Specialists use it to follow neuroendocrine tumours. On a general panel a raised value is far more often from an acid-suppressing medicine than anything else.
What commonly pushes it up
- Acid-suppressing medicines as a class (proton pump inhibitors), which raise it in almost everyone who takes them
- Kidney disease
- Long-term gastritis with low stomach acid
- Heart failure
- Neuroendocrine tumours
What commonly pushes it down
- Stopping an acid-suppressing medicine, after two weeks
Everyday reasons for a value outside the range
- Proton pump inhibitors are by far the commonest reason for a raised value
- Units and methods differ between labs
About the sample
The lab may ask for acid-suppressing tablets to be paused beforehand; this is decided by the requesting doctor.
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 freeThis 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.