预期应用

ELISA法定量测定鲑鱼血清、血浆或其它相关液体中降钙素含量。

 

实验原理

本试剂盒应用双抗体夹心酶标免疫分析法测定标本中降钙素水平。用纯化的抗体包被微孔板，制成固相抗体，往包被单抗的微孔中依次加入降钙素抗原、生物素化的抗鲑鱼降钙素抗体、HRP标记的亲和素，经过彻底洗涤后用底物TMB显色。TMB在过氧化物酶的催化下转化成蓝色，并在酸的作用下转化成最终的黄色。颜色的深浅和样品中的降钙素呈正相关。用酶标仪在450nm波长下测定吸光度（OD值），计算样品浓度。

 

Intended use

This immunoassay kit allows for the specific measurement of salmon Calcitonin concentrations in serum and plasma.

 

Introduction

The most prominent clinical syndrome associated with a disordered hypersecretion of Calcitonin is medullary carcinoma of the thyroid (MTC). MTC is a tumor of the Calcitonin producing C-cells of the thyroid gland. Although MTC is rare, comprising 5 - 10% of all thyroid cancer, it is often fatal. It may occur sporadically or in a familial form that is transmitted as an autosomal dominant trait. MTC has great clinical importance because of its familial distribution. Further, it leant itself to be diagnosed early by serum Calcitonin and total cure for early sub-clinical disease is possible1. This is frequently associated with other clinical features and it has good potential for cure with surgery. Although a rare tumor, it can occur in a familial pattern1 as a Type II multiple endocrine neoplasia. These tumors usually produce diagnostically elevated serum concentrations of Calcitonin. Therefore, the immunoassay for Calcitonin in serum can be used to diagnose the presence of MTC with an exceptional degree of accuracy and specificity. In the small but increasing percentage of patients, however, basal hormone levels are indistinguishable from normal1. Some of these subjects represent the early stages of C-cell neoplasia or hyperplasia that are most amenable to surgical cure. To identify these patients with early disease, provocative tests for Calcitonin secretion is necessary to preclude false negatives if only basal Calcitonin determination are performed. Most tumors respond with increased Calcitonin level to the administration of either calcium5 or pentagastrin6 or their combination, but either agent can still give misleading results. Therefore, in cases with clinical manifestations, both agents should be considered for diagnostic testing. Further, Calcitonin measurements can also be used to monitor the efficacy of therapy in patients with Calcitonin producing tumors. It has been reported that multiple forms of immunoreactive calcitonin are found in either normal subjects or patients with MTC. These various forms of calcitonin have molecular weights varying from 3,400 (monomeric) up to 70,000 Dalton (polymeric).Neoplastic disorders of other neuroendocrine cells can also elevate Calcitonin. The best example is small cell lung cancer. Other tumors such as carcinoids and islet cell tumors of the pancreas can also result in elevated serum Calcitonin. Increases in serum Calcitonin has also been noted in both acute and chronic renal failure, hypercalciuria and hypercalcemia.

 

Test principle

This assay employs the quantitative sandwich enzyme immunoassay technique. A monoclonal

antibody specific for Calcitonin has been pre-coated onto a microplate. Standards and samples are pipetted into the wells and any Calcitonin present is bound by the mmobilized antibody. An enzyme-linked monoclonal antibody specific for Calcitonin is added to the wells. Following a wash to remove any unbound antibody-enzyme reagent, a substrate solution is added to the wells and color develops in proportion to the amount of Calcitonin bound in the initial step. The color development is stopped and the intensity of the color is measured.