Highly sensitive chemiluminescence enzyme immunoassay for the quantification of carcinoembryonic antigen in the presence of an enhancer and a stabilizer

Using the advantages of phenol red, a signal enhancer, and bovine serum albumin (BSA), a stabilizer of horseradish peroxidase (HRP), added in HRP enzyme reaction of Amplex Red and H2O2, highly sensitive 1,1′-oxalyldiimidazole chemiluminescence enzyme immunoassay (ODI-CLEIA) was developed to rapidly quantify trace levels of carcinoembryonic antigen (CEA) in human serum. Phenol red acts as an enhancer in ODI-CLEIA while BSA supported rapid and stable activation of HRP. The CL emission of resorufin formed from the HRP enzyme reaction in the presence of BSA and phenol red was about 70-fold brighter than that in the absence of both materials. ODI-CLEIA in the presence of BSA (1.5 mg/ml).and phenol red (1 mM) was able to rapidly analyze CEA in human serum with the wide linear calibration curve (2.5–100 ng/ml). The limit of detection (LOD = 3σ/slope) of ODI-CLEIA was as low as 0.19 ng/ml. Additionally, it was confirmed that the accuracy, precision, and reproducibility of ODI-CLEIA in the presence of BSA and phenol red were good with the statistically acceptable error range.