From the Research
For patients with suspected PCOS, consider an MRI scan when prolactin levels exceed 85.2 ng/mL, as this level suggests the possibility of a prolactinoma rather than PCOS, as indicated by the most recent and highest quality study 1. When evaluating patients with suspected PCOS, it's essential to consider the prolactin level in the context of other clinical features and laboratory results.
- Mild elevations in prolactin (up to 50-60 ng/mL) can occur in PCOS due to increased estrogen levels affecting prolactin secretion.
- Significantly higher levels, however, warrant further investigation for pituitary tumors. Some key points to consider when ordering prolactin tests include:
- Collecting samples in the morning, with the patient in a fasting state and after minimizing stress, as these factors can temporarily increase prolactin levels.
- Conducting a thorough medication review, as certain medications like antipsychotics, some antidepressants, and metoclopramide can cause hyperprolactinemia. If prolactin levels are only mildly elevated (below 85.2 ng/mL) and the patient has typical PCOS symptoms like irregular periods, hyperandrogenism, and polycystic ovaries on ultrasound, an MRI may not be necessary, but clinical judgment should prevail based on the complete clinical picture, as suggested by 1. The study by 1 provides the most recent and highest quality evidence, indicating that a prolactin level of 85.2 ng/mL can distinguish patients with prolactinomas with 77% sensitivity and 100% specificity. Therefore, a prolactin level above 85.2 ng/mL should prompt consideration of an MRI scan to rule out a prolactinoma in patients with suspected PCOS.