Chromogranin A

You need to provide

Blood

This test is for

Male, Female

Test Preparation

No special preparation is required.
It is recommended that patient discontinues proton pump inhibitor drugs for at least 2 weeks prior to sample collection. Discontinuation should be with prior consent from the treating physician.

Understanding Chromogranin A

What is Chromogranin A?

A Chromogranin A test measures the amount of chromogranin A (CgA), a protein released by neuroendocrine cells (cells of endocrine (hormonal) and nervous systems) in the blood. It is also known as a tumor marker test because higher than normal levels of CgA are usually present in people with neuroendocrine tumors (NETs).

Neuroendocrine cells are found in various organs in the body and resemble both nerve cells and cells that make hormones. NETs develop due to abnormal growth of the neuroendocrine cells and they may be cancerous or non-cancerous. Such tumors occur most commonly in the gastrointestinal tract (GIT) (including large intestine, small intestine, and appendix), lungs, and pancreas. The symptoms of NETs may vary depending on the affected organs. For example, a tumor in the lung may cause wheezing or a persistent cough while a tumor in the GIT may cause diarrhea, constipation, or persistent stomach pain. It should be noted that a person may or may not show any symptoms and still demonstrate high CgA levels or develop a NET.

CgA levels can be elevated in people with many health conditions like atrophic gastritis, and impaired liver or kidney function. However, a Chromogranin A test typically helps with establishing a diagnosis and monitoring individuals with NETs. This test is the first-line diagnostic test for detecting carcinoid tumors, a type of NET. CgA may also be measured to help determine treatment response in NETs. Doctors may order this test to understand the course of the disease in known cases of NETs. In a few instances, your doctor may advise the test to check if the cancer has recurred.

There are no special preparations required before getting a Chromogranin A test done. However, it is recommended that a person discontinues the use of proton pump inhibitors for at least 2 weeks prior to sample collection to maintain test accuracy. Discontinuation should be with prior consent from the treating physician.

Test result ranges are approximate and may differ slightly between different labs depending on the methodology and laboratory guidelines. Talk to your doctor about your specific test results. Narrate your complete medical history to help the doctor correlate your clinical and laboratory findings. The results will help them determine your medical condition and formulate your overall treatment plan.

What is Chromogranin A used for?

A Chromogranin A test is done:

As a first-line diagnostic test for carcinoid tumors.
To monitor and manage ongoing treatment in neuroendocrine tumors (NETs).
To study disease progression or recovery.
To check for NET recurrence.

What does Chromogranin A measure?

A Chromogranin A test measures the amount of chromogranin A (CgA) in the blood. CgA is a protein released by neuroendocrine cells when triggered by the nervous system. Significantly elevated levels of chromogranin A in the blood are an indication of a neuroendocrine tumor (NET). This test is recommended by a physician if symptoms of a neuroendocrine tumor such as flushing of the face or neck, diarrhea, signs of intestinal blockage, rapid heart rate, chest pain, and difficulty in breathing, are suspected.

Frequently Asked Questions about Chromogranin A

Q. What is a Chromogranin A test?

A Chromogranin A is a blood test that measures the amount of CgA in the blood. CgA is a protein released by the neuroendocrine cells in response to triggers received from the nervous system. The test detects a neuroendocrine tumor (NET), helps monitor ongoing treatment for the same, and also helps check if the cancer has come back after treatment completion.

Q. What does a positive test result for Chromogranin A mean?

A positive test for Chromogranin A means that you may be suffering from a condition where CgA levels are higher than normal.

Q. I have tested positive for a Chromogranin A test. Does that mean I have cancer?

All positive test results of a Chromogranin A test do not imply that you have cancer. CgA levels may be detectable or high even in non-cancerous conditions such as rheumatoid arthritis, atrophic gastritis, etc. Prolonged use of certain medicines like proton pump inhibitors may also yield positive test results. Consult your doctor to understand your test results.

Q. Can a Chromogranin A test yield false-positive results? In what scenarios?

Yes, a Chromogranin A test may yield false-positive results in certain conditions. These include the use of proton pump inhibitors, cases of atrophic gastritis, and impaired liver or kidney function.