Prolactin and PCOS: a test that rules things out
Prolactin is a hormone made by the pituitary gland, best known for its role in breastfeeding. When it appears in a PCOS workup, it's usually there for a reassuring reason: to check whether something other than PCOS might explain your symptoms. Understanding why it's measured can take the worry out of seeing it on a request form.
What this test measures
A prolactin test measures the level of this pituitary hormone in your blood. Prolactin can be raised for a number of ordinary reasons, and levels can be affected by stress, timing and other factors, so a single reading is interpreted carefully and sometimes repeated. Reference ranges vary between labs and assays, which is why your result comes with its own range and why there's no universal figure to quote. A clinician reads it in the context of your wider picture.
Why it comes up in PCOS care
Irregular periods and related symptoms can have causes other than PCOS, and raised prolactin is one of them. So prolactin is often checked as part of ruling those alternatives out — which is part of how PCOS is diagnosed, since it's partly a diagnosis of exclusion. The NHS describes tests used to rule out other conditions when diagnosing PCOS. Seeing prolactin on your form usually means your clinician is being thorough, not that anything is wrong — that's reassuring, not alarming.
Keeping results across years
Even a test done to rule something out is worth keeping, because if prolactin is ever checked again, a clinician will want to compare. Results like these slip through the cracks between clinic systems easily, leaving each new test without its predecessor. A dated vault keeps your prolactin results in order alongside the rest of your panel, so a repeat reading has context — and so you're not searching old letters when someone asks what it was last time.
PCOS Diary keeps prolactin and your other results dated in the lab vault, so a repeat test has context to compare against in your doctor-ready PDF.
Common questions
- Why would prolactin be tested if I'm being assessed for PCOS?
- Because irregular periods can have causes other than PCOS, and raised prolactin is one of them. It's checked to help rule those alternatives out, which is part of how PCOS is diagnosed — seeing it on your form usually means thoroughness, not a problem.
- Should a single prolactin result worry me?
- Prolactin can be affected by stress, timing and other factors, so one reading is interpreted carefully and sometimes repeated. Reference ranges vary by lab. Any result is best understood in conversation with the clinician who ordered it.