Chromogranin A | Laboratory research

General Information

Chromogranin A is a member of the granin family of proteins found in the secretory vesicles of neuroendocrine cells. Their function is to regulate the secretory activity of the cell.

Chromogranin is an important marker in tissue tumors such as carcinoid, pheochromocytoma, neuroblastoma, medullary thyroid carcinoma, pituitary tumors, pancreatic islet tumors, apudomas, and others.

Serum chromogranin A concentration correlates with tumor size. It is also a sensitive marker for predicting residual tumors and recurrence.

Some carcinoid tumors secrete chromogranin A along with serotonin and peptides.

When is the survey conducted?

• Diagnosis and monitoring of carcinoid tumors (first-line diagnostic marker along with serotonin)
• Additional diagnostic marker for other neuroendocrine tumors

Patient preparation

Proton pump inhibitors (“antacids”) should be discontinued 1 week before the test sample is taken.

Research material – Venous blood

Interpretation of results

Most carcinoid tumors are characterized by an increase in chromogranin A concentration. For maximum sensitivity of the study, it is best to simultaneously determine the concentration of chromogranin, serum serotonin, and urinary 5-HIIIA (5-hydroxy-indole acetoacetate). If all three parameters are negative, the presence of a carcinoid tumor is excluded.

Because chromogranin A is metabolized in the liver and excreted by the kidneys, patients with progressive hepatic and renal failure often have elevated chromogranin A levels, which reduces its laboratory value.

Drugs that stimulate neuroendocrine cells, especially proton pump inhibitors, significantly increase serum chromogranin A concentrations.