Chromogranin A and B (CgA and CgB)
Chemical Pathology
Notes
- Chromogranin A is used as a marker for investigation and monitoring of neuroendocrine tumours.
- Increased levels of chromogranin A can also be seen in patients with decreased renal function, patients with atrophic gastritis, uncontrolled hyperthyroidism, and patients receiving proton-pump inhibitors.
- Chromogranin B is less affected by these factors and forms a useful adjunct to the more established chromogranin A measurement.
- Chromogranins are often assayed in conjunction with other peptides forming part of the "Gut hormone profile" which also includes VIP, CART, gastrin, glucagon and pancreatic polypeptide.
Sample requirements
Proton pump inhibitors need to be stopped for at least two weeks, and H2 (histamine 2 receptor) antagonists stopped for at least three days prior to testing where possible. The patient is not required to fast unless a gut hormone profile is also required.
For adults, blood taken into a 4mL EDTA tube sent immediately to the laboratory on ice (send 2 tubes on ice if full gut hormone profile required).
Storage/transport
Do not store, deliver immediately to the laboratory on ice. Plasma must be promptly separated and frozen on receipt in the laboratory.
Required information
Relevant clinical details including the reason for the request, whether the patient is fasting (not essential unless also requesting a gut hormone profile) and current medication.
Turnaround times
Samples are sent for analysis to a referral laboratory, with results expected back within four weeks.
Reference ranges
Chromogranin A: 0-60 pmol/L
Chromogranin B: 0-150 pmol/L
Further information
To learn more about chromogranins visit Lab Tests Online
Page last updated 15/03/2024