Chromogranin A (CGA)

Immunology

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Description

The main application of all tumour markers is monitoring for relapse or progression. Use as a diagnostic aid requires care and knowledge of the test limitations. Opportunistic screening is discouraged. Chromogranin A ( CgA ) is a 68kDa protein, which is produced by a variety of normal and malignant neuroendocrine and sympathetic neuronal cells [1]. Neuroendocrine tumours ( NET ) are a heterogenous group of neoplasms that are derived from peptide-and amine- producing cells of the neuroendocrine system [2]. Elevated levels of CgA are seen in neuroendocrine tumours ( NET ), including phaeochromocytoma, medullary Carcinoma of Thyroid, pancreatic islet cell adenoma and carcinoma, parathyroid adenoma, small cell carcinoma of lung and neuroblastoma. The diagnostic performance is influenced by the type of NET, CgA demonstrates a high sensitivity and specificity in phaeochromocytoma patients [1].

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Indications

Marker for monitoring neuroendocrine tumours ( Phaeochromocytoma, medullary Carcinoma of Thyroid, pancreatic islet cell adenoma and carcinoma, parathyroid adenoma, small cell carcinoma of lung and neuroblastoma ).

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Sample Type

2mL Serum ( Gel 5mL Yellow tube ) or 2mL Lithium Heparin or 2mL EDTA Plasma. Sample should be separated within 3 hrs of collection.
Requests from outside Sheffield: freeze sample prior to dispatch and transport frozen sample at ambient temperature via Royal Mail or Courier ( dry ice not required ).

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Reference Range

L0 - 6.0nmol/L (RIA method). 0 - 105ng/mL (Kryptor method). From 1st December 2023 for 1 year we will be running both assays side by side. New patients will have the Kryptor assay only. Patients who are being monitored and we have had sample previously will have both assays on the next sample we receive after 1st December 2023. This is to give a value that can be compared with previous values and a value on the new method that can be used for future comparison. Both these results will be on the same report. The assays give different numerical results but both follow the same trend. Reference ranges established by in-house validation of the manufacturers information

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Turnaround Time

Within 2 weeks

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Testing Frequency

Weekly

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References

PRU Handbook of Clinical Immunochemistry. 9th Edition. 2007. [Ref 1]
Mougey AM and Adler DG. Neuroendocrine tumours: Review and clinical update. Hosp Phys. 2007. 51:12-20. [Ref 2]
Seregni E, et al. Clinical significance of blood chromogranin A measurement in neuroendocrine tumours. Ann Oncol. 2001. 12( Suppl 2 ):S69-72
http://www.enets.org/guidelines_tnm_classifications.html

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Please note: the above information is subject to change and we endeavour to keep this website up to date wherever necessary.