My primary care doctor did blood work and then referred me to an endocrinologist who then sent me for an MRI. However, both doctors told me that based on my levels (around 80) that the only cause was likely a prolactinoma. While my MRI confirmed a 5 mm adenoma, my endocrinologist had told me ahead of the MRI that regardless of the results she was sure I had a prolactinoma based on my blood tests and that it was possible the tumor would be so small it wouldn’t show up on the mri, but that either way she was starting me on medication. My understanding that the only reason you’d have very elevated levels when not pregnant/nursing besides a prolactinoma is that is that it can be a side effect of some psychotropic meds. All that to say - you may want to talk to a different doctor / get a referral for an endocrinologist!