CHROMOGRANIN A

Message
***NEW METHODOLOGY AS OF 1-6-2020***
It is recommended that only one assay method be used consistently to monitor each patient's course of therapy.

Test Code
CHROMO A (LABCORP 140848)

CPT Codes
86316

Preferred Specimen
SERUM LG-RED


Patient Preparation
This test may exhibit interference when sample is collected from a person who is consuming a supplement with a high dose of biotin (also termed as vitamin B7 or B8, vitamin H, or coenzyme R). It is recommended to ask all patients who may be indicated for this test about biotin supplementation. Patients should be cautioned to stop biotin consumption at least 72 hours prior to the collection of a sample.

Minimum Volume
0.3-0.5mL SERUM ONLY

Specimen Stability
FROZEN 14 DAYS

Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
PLASMA

Methodology
EMPLOYS A TIME-RESOLVED AMPLIFIED CRYPTATE EMISSION  (TRACE) TECHNOLOGY BASED ON A NON-RADIOACTIVE ENERGY TRANSFER BETWEEN A DONOR (EUROPIUM CRYPTATE) AND AN ACCEPTOR (XL665) IN A SANDWICH IMMUNOFLUORESCENT FORMAT USING TWO MOUSE MONOCLONAL ANTIBODIES (35,36)

Limitations
Chromogranin A levels can be elevated in patients with severe renal failure.  Elevated levels of CgA are also common in patients on treatment with proton pump inhibitors. 
Values obtained with different assay methods or kits cannot be used interchangeably.

Reference Range
0.0−101.8 ng/mL

Clinical Significance
Human chromogranin A is 439-amino-acid protein with a molecular weight of 49 kilodaltons. It is a secretory protein that is produced by the dense-core vesicles of neuroendocrine cells. The physiologic role of this protein has not been fully elucidated, but it has been hypothesized that it may serve as a precursor to other biologically active peptides or may serve a function in the intracellular production of hormones and neuropeptides. Chromogranin A has been used as an immunohistochemical marker for normal and neoplastic neuroendocrine tissues.Elevated plasma concentrations have been demonstrated in patients with tumors of endocrine origin and levels have been shown to correlate with tumor volume. Several studies suggest that measurement of plasma chromogranin A may be a valuable diagnostic in subjects with tumors such as pheochromocytoma, carcinoid tumor, neuroblastoma, and small cell lung carcinoma. Neuroendocrine tumors that secrete no other hormone markers, referred to as “nonfunctioning” tumors, can sometimes be detected serologically because they retain the ability to secrete chromogranin A. Chromogranin A is more stable than serotonin, making its measurement a useful alternative for the detection of carcinoid tumor. Elevated levels of chromogranin A in patients with prostate cancer have been shown to correlate with poor prognosis.

Performing Laboratory
LABCORP DUBLIN,OHIO



The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.