Cannulated prolactin test in the diagnosis of the hyperprolactinemia syndrome

Hyperprolactinemia (HP) is a persistent pathological increase in a prolactin serum concentration amounting to more than 20 ng/ml in males and 25 ng/ml in females and leads to developing the pathological symptom complex of HP primarily from the reproductive system. To confirm the persistent etiology of HP and to eliminate physiological short-term hormone enhancement, a number of recommendations, including Russian and Belarusian, were proposed to make several prolactin measurements. This study included 120 patients with HP (96 females, 78.0 %) and (27 males, 22.0 %) aged 18–50 years who sought medical help at the Health Institution “Minsk City Clinical Endocrinology Center” in the period from December 2022 to September 2023. After catheterizing the vein, a venous cannula was inserted and blood was taken immediately after cannulating (T0), and then in 60 minutes (T1) and 120 minutes (T2). The cannulated prolactin test results were considered positive – with HP remaining in all three samples (T0, T1, T2), questionable – if HP was kept at T0 and T1, and negative if HP was only at T0. When evaluating the cannulated test results, true HP is 36.7 %. Patients with a positive cannulated test had a higher prolactin at T0, which was 888.5 mME/L ( U = 97.0; z = 7.92; p < 0.001). Patients with stress-induced HP (negative test) and patients with true HP (positive test) had no statistically significant differences in age and occurrence frequency of specific and non-specific complaints and symptoms for HP.