Endocrine Abstracts

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 who are 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 at the endocrine unit of one of the tertiary hospitals in Cameroon. Study participants were recruited from both endocrine and gynecological outpatient consultations 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 macroprolactinemia.

Results: We enrolled 33 women with a mean age of 31 ± 7 years (range 21-48). Twenty-seven (81.8%) participants were symptomatic with the majority 23/27 (69.7%) reporting 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 (80%) women with macroprolactinemia presented with symptoms, and there was no association between macroprolactinemia and symptoms of hyperprolactinemia among these participants.

Conclusion: Macroprolactinemia was detected in 5/33 (15.2%) of the study population. There was no association between macroprolactinemia and symptoms of hyperprolactinemia. Oligomenorrhoea, amenorrhoea, and galactorrhea were present in the majority of patients with macroprolactinemia hence routine screening for macroprolactinemia is recommended or advised in order to reduce the use of dopamine agonist treatment and imaging.

Keywords: Prolactin, Macroprolactin, PEG, Prolactin recovery rate, hyperprolactinemia