Endocrine Abstracts

Differentiating between true hyperprolactinaemia and stress induced hyperprolactinaemia can be difficult and may result in patients having unnecessary imaging and treatment.

Methods: The data for 89 patients who had a cannulated prolactin between January 2017 and September 2024 in the Royal University Hospital of Bath and Bristol Royal Infirmary has been analysed. The cannulated prolactin protocol used involved a cannula insertion and prolactin measurements at 0, 30, 60, 90 minutes.

Results: The mean baseline prolactin in this cohort was: Of the 89 patients, 70% (n=62) had a normal prolactin. Interestingly, 45 patients had a normal prolactin at baseline. Of those where the prolactin normalised, the nadir occurred at 90min. This highlights the importance of doing a full 90minute test in order to avoid false positive results. Of those with a normal result, 8 patients had an MRI pituitary. 4 showed a non-functioning pituitary adenoma and 4 MRIs were normal. Thus 54 MRIs were saved. With the estimated cost of an MRI pituitary being £300 and cannulated prolactin being £76, the estimated cost saving was £16,200. If you add the cost of outpatient appointments, the potential cost saving might have exceeded £20,000.

Conclusion: We have introduced a new endocrine nurse-led hyperprolactinaemia pathway in our trust for GPs to access.

1. Prolactin raised on 2 occasions in the community.2. If prolactin >3000 mIU/l then MRI pituitary and urgent referral to Endocrinology clinic.3. If prolactin level is between 700-3000 mIU/l then direct referral to endocrinology nurses to perform cannulated prolactin at 0 and 90 minutes. Lab only need to process the 90minute sample if the time 0 level is raised. If cannulated prolactin is <700 mIU/l then patient to be discharged back to GP; if cannulated prolactin is >700 then MRI pituitary, pituitary panel and Endocrinology appointment.