CgA
Pronunciation: see-gee-ay
Also written as: CgA — chromogranin A
Chromogranin A, a protein biomarker used for diagnosis and monitoring of neuroendocrine tumors.
Full Definition
Chromogranin A (CgA) is a 439-amino acid acidic glycoprotein that serves as a general biomarker for neuroendocrine tumors and other neuroendocrine conditions. It is stored in secretory granules of neuroendocrine cells throughout the body and is released along with hormones during exocytosis. Elevated serum CgA levels are found in 60-90% of patients with neuroendocrine tumors, making it useful for initial diagnosis, monitoring treatment response, and surveillance for recurrence. However, CgA can also be elevated in other conditions including proton pump inhibitor use, renal failure, heart failure, and other malignancies. Normal reference ranges vary significantly between laboratories and assay methods. Serial measurements are more informative than single values for monitoring disease progression or treatment response.
Usage
Usage note: Specify units and reference range; can be falsely elevated with PPI use.
In Context
- "Elevated CgA levels of 850 ng/mL supported the suspected diagnosis of neuroendocrine tumor." — Laboratory interpretation
- "CgA decreased from 400 to 180 ng/mL following three months of octreotide therapy." — Endocrinology follow-up note