Comparison of chemiluminescent microparticle immunoassay with electrochemiluminescence immunoassay for carcinoembryonic antigen
Introduction: Carcinoembryonic antigen (CEA) is used for monitoring of disease progression and treatment response in cancer patients. The aim was to compare the performance of chemiluminescent microparticle immunoassay with electrochemiluminescence immunoassay for CEA. Methods: A total of 115 samples were collected during routine diagnostic, prognostic, and therapy monitoring procedures in patients with colorectal and pancreatic cancer. We used Architect i2000SR and Cobas E601 for CEA analysis in sera samples. Results: The correlation coefficient of 0.984 (95% confidence interval [CI]: 0.972–0.991) for results obtained on both platforms was observed for CEA ≤10 ng/mL group. Moreover, intercept of 0.9027 (95% CI: 0.705–1.099) and slope 0.8076 (95% CI: 0.765–0.8498) (p < 0.0001) were observed in this group. In CEA >10 ng/mL group, we observed slope = 1.1986 (95% CI: 1.1474–1.2498) (p < 0.0001), intercept = –11.69 (–17.53–−5.84), and correlation coefficient = 0.985 (95% CI: 0.976–0.9914). Mean differences between assays in group ≤10 ng/mL and >10 ng/mL were 0.2066 (95% CI: 0.0019–0.4113) and –2.66 (95% CI: −10.10–4.76) ng/mL, respectively. Conclusion: Although there were differences, based on 20 days’ precision tests, overall results showed a good analytical performance and correlation between CEA assays on Architect i2000SR and Cobas E601 platforms. Reference intervals appropriate for the method of CEA measurement should be used. The standardization and harmonization of serum CEA concentration assays are needed.