Chromogranin A (CGA)

• ISI Order Code:

  CGA

• CPT Code:

  83520

Clinical Significance

Chromogranin A (CgA) is a 49 KD glycoprotein. Elevated levels are used to differentiate between neuroendocrine tumors and non-neuroendocrine tumors. In neuroendocrine tumors, approximately 50% have elevated levels of CgA. The serum CgA is most often elevated in Gastrinoma, pheochromocytoma, carcinoid tumors, non-functioning tumors of the endocrine pancreas, and medullary carcinomca of the thyroid.

Test order is recommended in combination with Pancreastatin and 5HIAA

• Reference Range:

  Up to 115.5 ng/ml

• Procedure:

  CgA is measured by immunoassay (EIA)

• Expected Turnaround Time:

  7-10 Business Days

Turnaround time is defined as the usual number of days from the date of receipt of a specimen for testing to when the result is released to the ordering facility.

• Report:

  Sample Report

Patient Preparation

The patient should fast for 10 to 12 hours prior to collection of specimen. Antacid
medications and medications that affect intestinal motility should be discontinued, if
possible, for at least 48 hours prior to collection of specimen.

Specimen Collection

3 ml serum or EDTA plasma should be collected and separated as soon as possible.  Minimum specimen size is 1 ml.

• Rejection Criteria:

  Gross hemolysis/lipemia/icteric

Special Specimens

For tumor/tissue and various fluids (e.g., CSF, peritoneal fluid, synovial fluid), contact
ISI for requirements and special handling instructions.

Shipping Instructions

Specimens should be shipped frozen in dry ice.