Reference values of human epididymis protein 4 in the Bulgarian population – assessment of the influence of age, menopause, pregnancy, and renal function

Human epididymis protein 4 (HE4) is increasingly utilized in diagnosing pelvic masses and monitoring patients with ovarian or endometrial carcinoma. However, various publications and diagnostic kit manufacturers report a wide range of reference and threshold values, complicating accurate clinical interpretation and reducing the marker's clinical utility. This study aimed to establish reference values for HE4 in the Bulgarian female population and investigate the impact of physiological factors such as age, menopause, and pregnancy, as well as pathological conditions like impaired renal function, on marker levels.