Chromogranin is a fairly reliable biomarker used to monitor patients with neuroendocrine cancers. Mine was up over 1800 last year then after a small liver resection dropped down to around 1000. I get tested every 4 weeks as am diagnosed with advanced metastatic paraganglioma. The endocrinologist says it is a good test which helps to determine tumor activity. As mentioned above there are other factors that can cause elevated levels to a certain point and each lab uses different methods for the test and they aren't interchangeable. Along with the pet scans chromogranin is another way the dr.s keep track of disease progression which in my case has been relatively eventful.
Good Luck

I’m tired. No cancer diagnosis. Lots of cancer in my family… mom, aunt, grandma and my sister died a year ago from breast, throat & lung cancers… she smoke and drank, as did my Mom. I have diarrhea most of the time, but had a section of colon removed a few years ago due to diverticulitis. Stomach issues with too much acid but haven’t taken any stomach meds since Feb because of protein pump thing, Last Chromogranin . was 1414 even off stomach meds. Thank you for your reply.