CLEIA CA125 evidences: good analytical performance avoiding “Hook effect”
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Cancer antigen 125 (CA125) is a coelomic epithelium-related antigen carried by a high molecular weight glycoprotein complex. It is commonly used as a tumor marker for ovarian cancer to monitor disease progression and response to therapy and as an early detection for recurrence after treatment. The aim of this study was to test the reliability of two different assay methods, a radioimmunometric assay (RIA) and an automated chemiluminescent enzyme immunoassay (CLEIA) system, by measuring CA125 serum levels using both methods in 357 patients and comparing the results. Patients were recruited from Oncologic Unit A, Policlinico Umberto I, Roma. Eighty-six were healthy donors, while 271 were oncologic patients representing a variety of diagnoses. Within this group, 76 patients were diagnosed with an ovarian related pathology (28 cancerous and 48 benign). The evaluation of CA125 marker blood levels showed a high agreement in healthy donors group (R2 = 0.9003). Interesting results emerged when sera collected from oncologic patients were assessed: significant differences between the two assays were found in nine samples. When assayed again with RIA after a dilution, new values agreed with undiluted CLEIA values (R2 = 0.9847). Our data suggest an overall good comparison between the two methods. However, some artifacts were obtained with RIA and indicate an underlying presence of “hook effect”. CLEIA automated assay showed a good reliability and should be preferred to one-step radioimmunoassays in order to minimize errors.
KeywordsCA125 biomarker Radioimmunoassay Chemiluminescence system
- 2.Duffy MJ. Tumor markers in clinical practice: a review focusing on common solid cancers. Med Princ Pract. 2012. doi:10.1159/000338393.
- 10.Bast RC, Klug TL, John St E, Jenison E, Niloff JM, Lazarus H, et al. A radioimmunoassay using a monoclonal antibody to monitor the course of epithelial ovarian cancer. N Engl J Med. 1983;309(15):883–7.Google Scholar
- 13.Granato T, Midulla C, Longo F, Colaprisca B, Frati L, Anastasi E. Role of HE4, CA72.4, and CA125 in monitoring ovarian cancer. Tumor Biol. 2012. doi:10.1007/s13277-012-0381-8.
- 14.Bast RC, Xu FJ, Yu YH, Barnhill S, Zhang Z, Mills GB. CA 125: the past and the future. Int J Biol Mark. 1998;13(4):179–87.Google Scholar
- 19.Anthony AM, Ermens AAM, van Duijnhove HLP, et al. Dilution protocols for detection of hook effects/prozone phenomenon. Clin Chem. 2000;46(10):1719–20.Google Scholar
- 23.Colman PG, Di Mario U, Rabizadeh A, Dotta F, Anastasi E, Eisenbarth GS. A prozone phenomenon interferes in islet cell antibody detection: direct comparison of two methods in subjects at risk of diabetes and in insulin dependent diabetics at onset. J Autoimmun. 1988;1(2):109–17.PubMedCrossRefGoogle Scholar
- 24.Wu JT. Diagnosis and management of cancer using serologic tumor markers. In: Henry JB, editor. Clinical diagnosis and management by laboratory methods. 19th ed. Philadelphia: WB Saunders; 1996. p. 1071.Google Scholar