Prolactin
Measures prolactin hormone levels to assess fertility, detect pituitary disorders, and evaluate symptoms like irregular periods or unexplained breast discharge.
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Lab testing services linked from this site are not available to residents of Alaska, Arizona, or Hawaii, unless otherwise noted on the lab's own website.
This publication is not intended to solicit the purchase of laboratory testing from any individual consumer.
What this test measures
Prolactin is a hormone produced by the pituitary gland that is best known for its role in initiating and maintaining breast milk production during and after pregnancy. However, prolactin participates in a much broader range of bodily functions, contributing to immune regulation, bone health, and reproductive processes in both sexes.
In individuals who are not pregnant or breastfeeding, prolactin normally circulates at low levels. Elevated prolactin outside of pregnancy and lactation (a condition called hyperprolactinemia) can suppress the reproductive hormones FSH and LH, potentially disrupting ovulation in women and reducing testosterone production in men. Common causes of elevated prolactin include pituitary adenomas (prolactinomas), certain medications, hypothyroidism, and stress. This test measures the amount of prolactin circulating in the bloodstream and is ordered to investigate menstrual irregularities, unexplained milk production (galactorrhea), infertility, reduced libido, and symptoms that may suggest a pituitary abnormality.
Who should consider this test
You might consider this test if you are experiencing any of the following:
- Individuals experiencing fertility challenges or difficulty conceiving, as high levels of prolactin can lead to infertility
- Women with irregular menstrual periods, missed periods, or experiencing no periods prior to menopause
- Those with unexplained breast tenderness, nipple discharge, or discharge in the breast when not pregnant or nursing
- Men experiencing decreased sex drive, difficulty getting an erection, or breast tenderness or enlargement
- Individuals being evaluated for suspected pituitary disorders or tumors
- Those taking medications that may affect prolactin levels, such as antipsychotic drugs or certain antidepressants
What to expect
Preparation
Most individuals require no special preparation, though some healthcare providers may recommend fasting for 8-12 hours before the test. Testing is typically scheduled in the morning, ideally 3-4 hours after waking, as prolactin levels naturally fluctuate throughout the day. Certain medications may affect results, so individuals should discuss their current medications with their healthcare provider.
Sample Type
A simple blood draw from a vein in the arm
Collection
During the lab visit, a healthcare professional will clean the skin and insert a small needle into an arm vein to collect the blood sample. The process typically takes less than five minutes and involves minimal discomfort. No doctor visit required - individuals can proceed directly to the lab for testing.
Turnaround
Results are typically available within 1-2 business days of sample collection
Understanding your results
Results are reported in nanograms per milliliter (ng/mL) and are interpreted based on sex, pregnancy status, and clinical context. Normal levels are typically low in non-pregnant individuals of both sexes, while significantly elevated levels during pregnancy and lactation are expected and physiologically appropriate. Mild elevations may be transient, caused by stress, recent exercise, or a meal before the blood draw. Persistently elevated levels warrant further investigation, as they may indicate a pituitary adenoma, medication side effect, or underlying hormonal condition. Healthcare providers evaluate prolactin alongside other reproductive hormones and, when indicated, pituitary imaging to determine the cause.
| Population | Reference Range | Notes |
|---|---|---|
| Adult Males | 2-18 ng/mL | Reference range for prolactin in males according to medical literature |
| Adult Females (Non-pregnant) | 2-29 ng/mL | Reference range for nongravid/nonlactating females |
| Pregnant Women (Third Trimester) | 10-209 ng/mL | Normal elevation during pregnancy to support milk production |
Reference ranges shown are general guidelines. Your lab report will include the specific reference range used by the laboratory that processed your sample, which is the authoritative range for interpreting your results.
What does a “Low” result mean?
Lower-than-normal prolactin levels are less common but may indicate pituitary gland dysfunction. Low prolactin levels are rare but may be a sign of a pituitary disorder, and without enough prolactin, a woman may not make enough milk to breastfeed after birth, which is usually the only symptom. One study found that a prolactin level of less than 5 ng/mL in women of reproductive age may increase a woman's risk of metabolic syndrome, which includes conditions that collectively increase risk of heart disease, stroke, and diabetes. Low levels may also suggest broader pituitary hormone deficiencies that require comprehensive evaluation.
What does a “High” result mean?
Elevated prolactin levels may indicate several conditions that warrant further evaluation. The most common cause is a prolactinoma, a benign (noncancerous) tumor growing on the pituitary gland that makes prolactin, which leads to higher-than-normal levels. Other potential causes include hypothyroidism, certain medications, kidney or liver disease, and chest injuries. In women, elevated prolactin can affect how the ovaries work and can cause menstrual problems and infertility, while in men, it can affect how the testicles work and can cause a lower sex drive and erectile dysfunction. Very high levels may require imaging studies to evaluate for pituitary tumors.
Privacy & confidentiality
All test orders are authorized and results reviewed by an independent, board-certified physician who is not the patient's personal doctor. Your prolactin test results are completely confidential and handled with the highest level of privacy protection. All testing is conducted with strict adherence to HIPAA regulations, ensuring your personal health information remains secure. Importantly, your test results are **not reported to your doctor** unless you specifically choose to share them, **not part of your medical records** unless you decide to add them, and **not on insurance statements** since you pay directly for testing. Your employer, insurance company, or government agencies cannot access your results without your explicit written consent. This confidential testing allows individuals to proactively monitor their hormonal health, assess fertility concerns, or follow up on symptoms without the results becoming part of their permanent medical record. Many people value this privacy when exploring sensitive health concerns or when seeking a second opinion about their hormone levels. You maintain complete control over who has access to your results and how they are used in your healthcare decisions.
Frequently asked questions
Related tests
FSH (Follicle Stimulating Hormone)
Often tested together since high prolactin can suppress FSH production, affecting fertility
View TestLH (Luteinizing Hormone)
Prolactin elevation can suppress LH levels, impacting ovulation and testosterone production
View TestThyroid Panel (TSH, T3, T4)
Hypothyroidism is a common cause of elevated prolactin levels and should be evaluated
View TestTestosterone (Total)
High prolactin can suppress testosterone production in men, affecting libido and fertility
View TestRelated conditions
Last reviewed: April 2026
CPT Code: 84146
This test may not be available in: NY, NJ, RI
This page is for informational purposes only and does not constitute medical advice. Always consult with a healthcare provider regarding any health concerns. LevelPanel does not diagnose, treat, or prescribe.
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LevelPanel has no business or affiliate relationship with Quest or LabCorp. These links are provided as a public service.
Lab testing services linked from this site are not available to residents of Alaska, Arizona, or Hawaii, unless otherwise noted on the lab's own website.
This publication is not intended to solicit the purchase of laboratory testing from any individual consumer.
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