Objective: To determine the correlation between the widely used CA125 assay and a second-generation assay, CA125 II, in a large population of women to determine the utility of measuring CA125 levels in the diagnosis of benign gynecologic disease.
Methods: A total of 822 patients who presented to a gynecology clinic completed a medical questionnaire and underwent a physical examination. Blood samples were obtained to determine serum CA125 levels. Hospital charts were reviewed, and diagnoses were correlated with serum CA125 levels as measured by the CA125 and CA125 II assays.
Results: CA125 and CA125 II assay values were highly correlated within four subject categories: age, ethnicity, smoking history, and menstrual category. Mean values decreased with increasing age but were unchanged across ethnic groups and cigarette-smoking status. When means were compared for results of the second-generation and current assays, little difference was found in the age, ethnicity, and smoking categories. Mean serum CA125 values on the CA125 II assay exceeded those on the CA125 assay when obtained during the menstrual and follicular/luteal phases of the menstrual cycle, but they did not differ in anovulatory, pregnant, and menopausal women or in those patients taking hormonal medications. CA125 levels were elevated on both assays in women with fibroids and were higher on the CA125 II assay than on the CA125 assay in women with benign ovarian cysts.
Conclusions: Serum CA125 levels obtained using the CA125 II assay are closely correlated with those obtained using the more familiar CA125 assay. In the diagnosis of benign gynecologic disease, the usefulness of a single serum level measured with the newer CA125 II assay was the same as that of a single CA125 assay level.