Human Chromogranin A CLIA Kit

Background

​​​​​​​The EDI™ Human Chromogranin A Chemiluminescence Immunoassay (CLIA) kit is designed, developed, and produced for the quantitative measurement of human chromogranin A level in serum samples. The assay utilizes a two-site “sandwich” technique with two antibodies that bind to different epitopes of chromogranin A. Assay calibrators, controls, or patient serum samples are added directly to a reaction vessel together with streptavidin coated magnetic particles and biotinylated anti-chromogranin A polyclonal antibody. After an incubation period, a wash step is introduced and an acridinium ester conjugated anti-chromogranin A monoclonal antibody is added to each reaction vessel. The magnetic particles capture the biotin antibody as well as an immuno complex in the form of “magnetic particles–biotin chromogranin A antibody–chromogranin A–acridinium ester chromogranin A antibody”. Materials bound to the solid beads are held in a magnetic field while unbound materials are washed away. Then, trigger solutions are added to the reaction vessel and light emission is measured with the ECL100 or ECL25 analyzer. The relative light units (RLU) are proportional to the concentration of a chromogranin A in the sample. The amount of analyte in the sample is determined from a built-in multi-point calibration curve and reported in serum chromogranin A concentration.

Product Summary

​​​​​​​Chromogranin A is a 49 kDa acidic protein that consists of 439 amino acids encoded on chromosome 14. Chromogranin A has been identified in a number of normal and neopastic endocrine tissues. It is demonstrated that an elevated level of circulating chromogranin A is a marker for tumors of neuroendocrine origin. However, the most significant clinical use of chromogranin A is related to the diagnostic procedure in patients with pheochromocytoma. The following is a short summary of the potential usages of chromogranin A.
1. A very sensitive (83%) and highly specific (96%) marker in the evaluation of actual or suspected pheochromocytoma. Drugs commonly employed in the diagnosis or treatment of pheochromocytoma have little effect on the plasma chromogranin A level, which is a great advantage of measuring chromogranin A over catecholamines.
2. To ascertain the source of a tumor. A high chromogranin A level indicates that the tumor arises from neuroendocrine tissues.
3. Endocrine tumors that do not produce their specific hormones, for example, calcitonin negative but chromogranin A positive, C-cell carcinoma; zero-cell carcinoma; beta-cell carcinoma; parathyroid carcinoma.

Selected Literature

1. Rafael Molina, et al. Evaluation of chromogranin A determined by three different procedures in patients with benign diseases, neuroendocrine tumors and other malignancies. Tumor Biol. 2011; 32:13–22
2. S L Burgio, V Conteduca, et al. Chromogranin A predicts outcome in prostate cancer patients treated with abiraterone. Endocrine-Related Cancer 2014; 21, 487–493
3. Nikou, G. C., Lygidakis, N. J., Toubanakis, C., Pavlatos, S., Tseleni-Balafouta, S., Giannatou, E., Mallas, E., &Safioleas, M. (2005). Current diagnosis and treatment of gastrointestinal carcinoids in a series of 101 patients: the significance of serum chromogranin-A, somatostatin receptor scintigraphy and somatostatin analogues. Hepato-gastroenterology, 52(63), 731–741.
4. Wu, J. T., Erickson, A. J., Tsao, K. C., Wu, T. L., & Sun, C. F. (2000). Elevated serum chromogranin A is detectable in patients with carcinomas at advanced disease stages. Annals of clinical and laboratory science, 30(2), 175–178.

For in-vitro diagnostic use.