Enzyme-linked immunosorbent assay of CA-125 in serum of patients with endometriosis: Efficacy in diagnosis

Abstract

We used an enzyme-linked immunosorbent assay to quantify CA-125, a cancer antigen, in serum of patients with endometriosis. Concentrations of CA-125 in 103 patients with untreated endometriosis significantly (P < 0.005) exceeded those for 31 controls with no evidence of disease: 9.1 (SD 12.3) vs 2.2 (SD 3.2) arb. units/mL. Values for patients with treated endometriosis were lower (2.3, SD 2.6, arb. units/mL, n = 9) than those for patients with untreated endometriosis. The mean concentrations of CA-125 in different stages of untreated endometriosis were 4.8 (SD 4.5), 7.1 (SD 9.9), 9.8 (SD 13.2), and 10.8 (SD 13.0) arb. units/mL for Stages I, II, III, and IV, respectively. The differences between controls and each stage were statistically significant (for all stages: P < 0.05). We also assayed serum sampled from controls and patients with untreated endometriosis during menstruation (Group A) and during nonmenstruation (Group B). The efficacy of the present assay for concentrations of CA-125 in serum of patients with endometriosis was greater for Group B than for Group A. Evidently, determination of CA-125 in serum by the present assay may assist in such diagnosis.