A prolactin test measures the level of
hormone prolactin, which is made by the
pituitary gland, in your blood. Prolactin levels are
different throughout the day. The highest levels occur during sleep and shortly
after you wake up.
The normal values listed here—called a reference range—are just a guide. These ranges vary from lab to lab, and your lab may have a different range for what's normal. Your lab report should contain the range your lab uses. Also, your doctor will evaluate your results based on your health and other factors. This means that a value that falls outside the normal values listed here may still be normal for you or your lab.
| Nonpregnant women |
4–23 nanograms per milliliter (ng/mL) or 4–23 micrograms per liter (mcg/L)
| Men |
3–15 ng/mL or 3–15 mcg/L
|Pregnant women |
34–386 ng/mL or 34–386 mcg/L
3.2–20 ng/mL or 3.2–20 mcg/L
- High levels of prolactin (usually higher than 200
ng/mL) may mean a pituitary gland tumor (prolactinoma) is present. The higher
the prolactin level, the more likely a pituitary gland tumor is present. If a
prolactin level is over 200 ng/mL, a
magnetic resonance imaging (MRI) test may be done to
confirm a pituitary tumor is present. A normal or low prolactin level does not
always mean there is no pituitary tumor. An MRI test may be done if a pituitary
tumor is suspected.
- High levels of prolactin may
mean that the pituitary gland is making excess prolactin for unknown reasons
- Other conditions that can cause
high prolactin levels include pregnancy, liver disease (cirrhosis), kidney disease, and
Many conditions can affect prolactin levels. Your doctor will talk with you about any abnormal results in relation to your
symptoms and past health.
Sarah Marshall, MD - Family Medicine
Deborah A. Penava, BA, MD, FRCSC, MPH - Obstetrics and Gynecology
August 1, 2012
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