Chromogranin A (CgA)
Chromogranin A (CgA) is a protein commonly secreted by neuroendocrine tumor cells. A blood test measures CgA as a tumor marker. In patients treated with somatostatin analogs, CgA tests should be timed carefully with their somatostatin analog treatment. False-positive levels of CgA, due to several issues, including the use of proton pump inhibitors (medications used to treat heart burn), may occur.16
Complete blood count (CBC)
A CBC measures different types of blood cells, including red blood cells, white blood cells, and platelets. It also measures the amount of hemoglobin (the protein that carries oxygen) in the blood, the percentage of the total blood volume that is taken up by red blood cells (hematocrit), the size of the red blood cells, and the amount of hemoglobin in red blood cells.
Fasting serum tests
These types of tests measure the amount of gastrin, sugar, VIP, or somatostatin in the blood. Patients may need to fast for at least 8 hours for these tests.6
6Cancer.NET Editorial Board. Neuroendocrine Tumor of the Pancreas: Symptoms and Signs. 2017. https://www.cancer.net/cancer-types/neuroendocrine-tumor-pancreas/symptoms-and-signs. Accessed October 22, 2018.
16Mayo Clinic Laboratories. Test ID: Chromogranin A. https://www.mayocliniclabs.com/test-catalog/Clinical+and+Interpretive/34641. Accessed December 21, 2018.