Chromogranin A, Serum

Casandra

Casandra Test Code MC32416Version 1 (DRAFT)

Performing Lab

Lab Mayo Clinic LabLab Test ID CGAKCPT Code 86316

Chromogranin A, Serum

Clinical Use

Use

Chromogranin A (CgA) is a useful diagnostic marker for neuroendocrine neoplasms, including carcinoids, pheochromocytomas, and neuroblastomas. It aids in monitoring disease progression during the course of disease and treatment in patients with gastroenteropancreatic neuroendocrine tumors (grade 1 and grade 2) when used in conjunction with other clinical methods. CgA is particularly suited for diagnosing hindgut tumors and is elevated in most patients with symptomatic or advanced carcinoids. It also helps in the differential diagnosis of isolated symptoms suggestive of carcinoid syndrome.

Special Instructions

For at least 2 weeks before specimen collection, patients should stop taking proton pump inhibitor medications to avoid false elevations of serum CgA levels. Serum should be centrifuged and aliquoted into a plastic vial. Do not submit in original collection tube. Forms such as General Request or Oncology Test Request must accompany the specimen if not ordering electronically.

Limitations

This test should not be used for cancer screening or diagnosis. It is not indicated to be used as a stand-alone monitoring assay. Single serum CgA measurements may be uninterpretable in patients with impaired kidney function. Serial measurements are required for accurate assessment. Drugs affecting neuroendocrine secretion, like proton pump inhibitors, may cause artifactual elevations. Different assay methods might produce variable results due to differences in assay technologies.

Test Details

FDA Approved