Endocrine Abstracts

Introduction: One of the most common referrals to a general endocrine clinic is hyperprolactinemia. It’s very difficult to differentiate between stress induced hyperprolactinaemia and true hyperprolactinaemia and may result in unnecessary endocrinology appointments and imaging.

Methods: We have collected data for 60 patients who had a cannulated prolactin test between January 2017 and April 2024 in the Royal United Hospital of Bath (RUH). After cannula insertion, prolactin was measured at 0,30,60 and 90 minutes.

Results: After cannulated prolactin: 30% confirmed high prolactin and 70% confirmed normal results. 42 normal results when did nadir prl occur: 0 min sample: 5%; +30 min sample: 7%; +60 min sample: 7%; +90 min sample: 81%. 18 abnormal results when did nadir prl occur: 0 min sample: 6%; +30 min sample: 22%; +60 min sample: 33%; +90 min sample: 39%. This highlights important to do a full 90 min test given nadir most commonly occurs at 90 mins in both groups, although a bit more spread out in the abnormal test results. 16 patients (26,6%) with abnormal prolactin had MRI performed and 2 patients were still waiting. As a result of this test, we have saved 41 MRIs as just one patient with a normal cannulated prolactin had MRI pituitary and it was normal. His MRI was performed before the cannulated prolactin. Total cost of MRI: £300. Total cost of completing a cannulated prolactin test: £ 76.11. Total cost of 2 outpatients appointments: £372. Therefore, we have saved £ 12,300 and we have saved 2 outpatient appointments per patient which means that we have saved another £ 15,252.

Conclusion: Cannulated prolactin is a very good cost-effective test for diagnosing true hyperprolactinaemia. In summary, we are planning to introduce a new pathway for Hyperprolactinaemia which should include: referral to endocrinology after 2 raised consecutive prolactin in primary care should be made, endocrinology will arrange a 90 min cannulated prolactin test, if still abnormal: arrange MRI pituitary and 2 clinic appointments.