Establishment and Evaluation of a New Chemiluminescent Enzyme Immunoassay for Carcinoembryonic Antigen Adapted to the Fully Automated ACCESS^®System

Abstract

We have established a new chemiluminescent enzyme immunoassay for Carcinoembryonic antigen (CEA), designated ACCESS CEA, which is adapted to the fully automated ACCESS® immunoassay analyzer. The assay is based on a one step sandwich-type method using two monoclonal antibodies, one of which is immobilized on micrometer-size paramagnetic particles and the other is conjugated to alkaline phosphatase. Ten microliters of calibrators or sera are incubated for 5 minutes at 37 °C with the particles and with the alkaline phosphatase conjugate. The particles are then magnetically separated and washed to remove unbound components. Time needed to obtain the first result is less than 15 minutes.The assay range was 0.04-1000 μg/l of CEA, and the possible high-dose hook effect was prevented at CEA concentrations up to 100000 μg/l in this working range. The coefficient of variation (CV) for intra-assay precision was 3.0 to 4.7%, and inter-assay CV was 3.4 to 5.6%. The sample carryover was less than 0.001%. The analytical recovery ranged from 98 to 104% and a dilution linearity was demonstrated. No interference was detected in any sample with levels up to 300 mg/1 for bilirubin, 12000 mg/1 for haemoglobin, 50000 mg/1 for human serum albumin, 8 500 mg/1 for triacylglycerol, and 500 000 IU/1 for rheumatoid factor. The ACCESS CEA assay also showed very homogeneous reactivity with purified CEA preparations from different tumours and could discriminate CEA from four CEA-related normal antigens tested.Serum samples (n = 362) from patients with malignant or non-malignant disease, as well as from healthy individ-

Comparison of Four Automated Carcinoembryonic Antigen Immunoassays: ADVIA Centaur XP, ARCHITECT I2000sr, Elecsys E170, and Unicel Dxi800

“…This might be due to the fact that these two immunoassay analyzers use a single monoclonal antibody for two-step sandwich immunoassay, while the other two assays use one or more different antibodies. Several comparative studies of CEA assays have been reported [ 12 15 18 19 20 ]. In one of these studies, CEA data obtained by Unicel DxI800 showed the highest degree of correlation with those measured by ADVIA Centaur XP [slope (95% CI), 0.910 (0.883 to 0.947); intercept (95% CI), −0.240 (−0.362 to −0.171)] [ 19 ].…”

“…Therefore, it is important to choose an appropriate curve-fitting model for calibration curves and to consider all calibration curve-related factors, including quality and stability of reference standards, quality and stability of reagents, and statistical validity of the calibration curve [ 10 11 ]. Although various CEA assays with different principles, including chemiluminescence immunoassay (CLIA), enzyme immunoassay, radioimmunoassay, fluorescence immunoassay, and lateral flow immunoassay have been introduced, currently, automated CLIA analyzers with high sensitivity and high throughput are the most widely used [ 12 13 14 ]. Despite ongoing standardization efforts, CEA concentrations from different manufacturers can vary owing to the lack of accurate calibration as well as differences in assay principle, the epitope used, antibody specificities, and the reagents used.…”

Interaction Analysis of the Carcinoembryonic Antigen (CEA) with Its Monoclonal Antibody Immobilized on a Gold Surface Using Fourier Transform Infrared Reflection-Absorption Spectroscopy (FT-IR RAS)

“…11,14 We firstly tried to detect human CEA without using a second antibody. Human CEA was subjected to the CEA monoclonal antibody-immobilized gold surface (Fig.…”

“…10 However, it is also known that CEA often gives a high rate of false positive signals. 11 When the FT-IR RAS measurement can be applied to this assay system, it should give a reduced rate of false positive signals because of its structural information. The concept of the immobilization of a CEA monoclonal antibody on a gold surface and its interaction assay with CEA are shown in Fig.…”

Top-down nanofabrication of silicon nanoribbon field effect transistor (Si-NR FET) for carcinoembryonic antigen detection

“…On-time, sensitive, and repeatable detection of CEA are crucial for the early diagnosis and treatment of those diseases. Classical labeled immunosensors techniques, including enzyme-linked immunosorbent assay (ELISA), 4,14 radioimmunoassay (RIA), 15 and chemiluminescent enzyme immunoassay (CLEIA), [16][17][18] are time consuming and require expensive optical equipment for characterization. Label-free and real-time detection is required by clinical application.…”