Human Carcinoembryonic Antigen (CEA) ELISA Kit

INTENDED USE

This Human Carcinoembryonic Antigen ELISA Kit is designed for in vitro quantitative determination of Carcinoembryonic Antigen (CEA) concentrations in human serum and plasma samples.  The kit is intended for RESEARCH USE ONLY and should not be used in any diagnostic or therapeutic procedures.

INTRODUCTION

Carcinoembryonic Antigen (CEA) is a 180-200 KD glycoprotein expressed at high level in the epithelial cells of the embryonic colon.  The expression is stopped after birth.  CEA serum content is low in normal population and only slightly elevated in heavy smokers.  CEA level is increased in some types of cancer.  However elevated CEA level not necessarily indicates neoplastic conditions, since high CEA expression has been observed in non-neoplastic conditions such as ulcerative colitis, pancreatitis and cirrhosis.  CEA elevation is known to be affected by multiple factors.  Therefore, CEA test is not reliable for diagnosis or screening of cancer.

CEA belongs to the immunoglobulin superfamily.  In human, CEA family consists of a large number of complex molecules with cell adhesion function.  The genes are located within a 1.2 MB cluster on the long arm of chromosome 19.  The prototype adhesion molecules of the family are known as C-CAMs (cell-cell adhesion molecules).  These molecules are multi-functional, signal-regulated proteins that may implicate with various cell functions including tissue differentiation, angiogenesis, apoptosis, metastasis and the modulation of immune responses.  This ELISA kit provides a useful tool for studying the expression and regulation of the antigen.

PRINCIPLE OF THE ASSAY

This CEA enzyme linked immunosorbent assay (ELISA) kit uses a technique called quantitative sandwich immunoassay.  The microtiter plate provided in this kit has been pre-coated with a monoclonal antibody specific for CEA.  During the assay, standards or samples are added to the microtiter plate wells and CEA, if present, will bind to the CEA antibody pre-coated on the wells.  Then, a preparation of horseradish peroxidase (HRP)-conjugated CEA antibody is added to each well.  The conjugated antibody will bind to the CEA immobilized on the plate after incubation.  All unbound components will be removed by subsequent washing procedure.  Afterwards, 3, 3', 5, 5' tetramethyl-benzidine(TMB), a substrate for HRP is added to each well.  The colorimetric reaction is proportional to the CEA content in each well.  The reaction is terminated by the addition of a sulphuric acid solution and the colour change is measured spectrophotometrically at the wavelength of 450nm ± 2nm.

In order to quantify the amount of CEA present in the sample, the calibration standards should be assayed at the same time as the samples to allow the operator to produce a standard curve of Optical Density (O.D.) versus CEA concentration (ng/mL).  The concentration of CEA in the samples is then determined by comparing the O.D. of the samples to the standard curve.

CITATIONS  

1. Viraka Nellore BP, Kanchanapally R, Pramanik A, Sinha SS, Chavva SR, Hamme A 2nd, Ray PC.Aptamer-conjugated graphene oxide membranes for highly efficient capture and accurate identification of multiple types of circulating tumor cells. Bioconjug Chem 2015; 2(26):235-42.