Hello @willam,

Here is a list of some of the tests (from the Carcinoid Cancer Foundation website) that are used in helping to diagnose NETs.
https://www.carcinoid.org/for-patients/diagnosis/diagnosis-and-follow-up-tests/
As you can see, there are blood tests, 24-hour urine tests as well as scans. Your diagnosis usually comes from numerous diagnostic workups.

From what you have posted in the past, it appears that a tumor has not been found. Is my understanding correct?