At a glance
Also known as
Why get tested?
To help diagnose and monitor and other tumours
When to get tested?
When you have symptoms suggestive of a carcinoid tumour, such as flushing, diarrhoea, and/or wheezing; when your healthcare provider thinks that you may have a carcinoid or other neuroendocrine tumour
A blood sample drawn from a vein in your arm
Test preparation needed?
Fasting may be required; follow any instructions from your healthcare provider or laboratory
What is being tested?
Chromogranin A (CgA) is a released from cells. These are cells that secrete in response to signals from the nervous system. They are found in organs throughout the body. This test measures the amount of chromogranin A in the blood.
Neuroendocrine cells, and the glands that they are found in, can give rise to a variety of , both and . Examples include , insulinomas, small cell lung cancers, and neuroblastomas. The CgA test may be used to help detect, diagnose, and/or monitor neuroendocrine tumours, especially carcinoid tumours.
Many of these tumours release large quantities of the hormone associated with that tissue, either continuously or intermittently, causing symptoms characteristic for that tumour. However, not all neuroendocrine tumours release the expected hormones. In either case, neuroendocrine tumours are frequently associated with increased concentrations of CgA.
Carcinoid tumours are slow-growing noncancerous or cancerous masses that form mainly in the gastrointestinal tract (especially in the appendix) and in the lungs. Most remain small and do not cause any symptoms. When carcinoid tumors are discovered in patients during surgical procedures performed for other reasons, they are called "incidental" tumours. A small percentage of these tumours may eventually grow large enough to cause obstructions in the intestines or bronchial tubes of the lungs.
How is the sample collected for testing?
A blood sample is obtained by inserting a needle into a vein in the arm.
Is any test preparation needed to ensure the quality of the sample?
No test preparation is needed unless fasting is required. Follow any instructions from the healthcare provider or laboratory.