Test Directory

Chromogranin-A (CgA) is an acidic glycoprotein expressed in the secretory granules of most normal and neoplastic neuroendocrine (NE) cell types, where it is released together with peptide hormones and biogenic amines. Neuroendocrine tumors (NETs) are a form of cancer that differ from other neoplasia in that they synthesize, store, and secrete peptides, e.g., CgA and amines. CgA is secreted from neuroendocrine-derived tumors including foregut, midgut and hindgut gastrointestinal NETs, pheochromocytomas, neuroblastomas, medullary thyroid carcinomas, some pituitary tumors, functioning and non-functioning pancreatic NETs.

Significantly elevated CgA levels have been found in patients with other diseases, such as impaired renal function, untreated benign essential hypertension, gastritis, prostatic carcinoma, and hyperparathyroidism. The best-characterized circulating biomarker that identifies NETs in general is CgA. Monitoring blood CgA levels may effectively provide information that is helpful in delineating tumor burden and rate of tumor growth, predicting tumor response to therapy and providing some indication as to prognosis.

Specimen Type: Serum

Collection Container: Red Top, Plain

Desired Specimen Volume: 1 mL

1. Collect a red top, plain tube via venipuncture.

1. Let specimen clot for no longer than 1 hour.
2. Separate serum from cells immediately.
3. Transfer 1 mL of serum to a clear aliquot tube (screw cap).
4. Freeze immediately. Do not store refrigerated.

Transport to the laboratory frozen. 

• Gross hemolysis
• Unspun red-top (no gel) tubes
• Serum separator tube

See patient report.

• CgA