Plasma tetranectin was measured in 67 controls, 121 patients with a benign or malignant ovarian tumor, and 24 patients with another benign gynecologic disease to evaluate the predictive value of plasma tetranectin. A significant reduction of plasma tetranectin was found in every malignant tumor type except for mucinous tumors. Further a significant correlation was found between stage of tumors and plasma tetranectin. Depending on the cutoff level the sensitivity for stage 1 cancer ranged from 52 to 71%. In stage 1 + 2 the sensitivity ranged from 58 to 75% and for advanced cancer (stage 3 + 4) from 80 to 95%. The corresponding specificities ranged from 97 to 84%. Plasma tetranectin may be a useful tool for detecting early stages of ovarian cancer.