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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.
Values obtained with different assay methods should not be used interchangeably in serial testing. It is recommended that only one assay method be used consistently to monitor each patient's course of therapy. If serial monitoring is required, please use the serial monitoring number 480847 to order.
Serum or plasma
0.1 mL (Note: This volume does not allow for repeat testing.)
Red-top tube, gel-barrier tube, lavender-top (EDTA) tube, or green-top (heparin) tube
Separate serum or plasma from cells and transfer to a plastic transport tube.
Causes for Rejection
Non-EDTA or nonheparinized plasma received; frozen red-top tube received; grossly hemolyzed specimen
Detect neuroendocrine cancers
Chromogranin A levels can be elevated in patients with severe renal failure.1 Elevated levels of CgA are also common in patients on treatment with proton pump inhibitors.2
This procedure may be considered by Medicare and other carriers as investigational and, therefore, may not be payable as a covered benefit for patients.
Results for this test are designated to be for research purposes only by the manufacturer. The performance characteristics of this product have not been established. Results for this test should not be used as absolute evidence of presence or absence of malignant disease without confirmation of the diagnosis by another medically established diagnostic product or procedure. Values obtained with different assay methods or kits cannot be used interchangeably.
Enzyme-linked immunosorbent assay (ELISA)
Human chromogranin A is 439-amino-acid protein with a molecular weight of 49 kilodaltons.3,4 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.5 Elevated plasma concentrations have been demonstrated in patients with tumors of endocrine origin and levels have been shown to correlate with tumor volume.6 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.7 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.8 Elevated levels of chromogranin A in patients with prostate cancer have been shown to correlate with poor prognosis.9
|Order Code||Order Code Name||Order Loinc||Result Code||Result Code Name||UofM||Result LOINC|
|140848||Chromogranin A||25587-7||140852||Chromogranin A||nmol/L||25587-7|