Relevance and Therapeutic Implication of Macroprolactinemia Detection Using PEG 6000 in Women of Childbearing-Age with Hyperprolactinemia: Experience of a Tertiary Hospital

Abstract

Introduction: Macroprolactin (MacroPRL), a variant of human prolactin, may interfere with hormonal assay and falsely increase serum prolactin levels. Therefore, failure to identify macroprolactinemia can lead to inappropriate investigations and treatment in women already susceptible to anxiety and stress. We aimed to identify macroprolactinemia among women of childbearing age with hyperprolactinemia. Materials and methods:We conducted a cross-sectional study in a tertiary care setting at the endocrine unit. Study participants were recruited from both endocrine and gynecological outpatient consultation services. They were women of childbearing age (18 to 49 years) consulting for signs and symptoms of gonadal dysfunction or hyperprolactinemia (PRL > 25 ng/ml). Total prolactin was measured using a Human direct ELISA method. Polyethylene glycol 6000 (PEG 6000) precipitation was used to detect macroprolactin. Results:We enrolled 33 women with a mean age of 31 ± 7 years (range 21-48). Twenty-seven (81.8%) participants were symptomatic, and the majority, 23/27 (69.7%) reported having galactorrhea, and 21 (63.4%) women reported having an irregular menstrual cycle. The median pre-precipitation prolactinemia reduced significantly after PEG precipitation from 61.2 (IQR: 33.2-115.9) ng/ml to 33.8 (IQR: 17.9-70.5) ng/ml, p < 0.001. After PEG precipitation 5 participants had a serum prolactin recovery rate below 60%, and therefore a prevalence of macroprolactinemia at 15.2%. Four out of five (80%) women with macroprolactinemia presented with symptoms which were (Amenorrhea, oligomenorrhea and galactorrhea). Conclusion:PEG 6000 permitted the detection of macroprolactinemia in women of childbearing age with hyperprolactinemia who otherwise would have been subjected to unnecessary medical investigations and treatment. Also, most of those with macroprolactin were symptomatic contrary to previous postulates.