Prolactin Test
A prolactin test measures prolactin, a hormone made by the pituitary gland. Clinicians often use it to help evaluate a range of reproductive and hormonal questions.
About this test
Prolactin is a hormone produced by the pituitary gland, a small structure at the base of the brain. It is best known for its role in milk production after childbirth, but it is present in everyone and takes part in reproductive and hormonal signaling more broadly.
The prolactin test is performed with a routine blood draw at a patient service center, where a phlebotomist collects a sample from a vein in the arm and sends it to the laboratory. Prolactin can rise temporarily with things like sleep, stress, or recent activity, so a clinician often considers the circumstances of the draw when reviewing a result.
Who might consider this test?
- Often exploring questions related to menstrual cycles
- Unexpected milk production
- Other symptoms that can be linked to hormonal signaling
Test details
| Quest code | 746 |
|---|---|
| Methodology | Immunoassay |
| Sample type | 1 mL serum |
| Patient preparation | Fast overnight before your blood draw if you can. |
| Collection | Quest patient service center |
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Additional details
What prolactin does
Prolactin's most familiar role is supporting milk production, but its influence extends into broader reproductive and hormonal signaling in people of any sex. The pituitary adjusts prolactin as part of a wider hormonal conversation, which is why a clinician may consider it when looking into cycles, fertility, or related concerns. Measuring it gives a window into that part of the pituitary's activity.
A single prolactin result is a snapshot. Levels can rise briefly in response to everyday factors such as sleep, stress, or recent physical activity, so a clinician interprets a value in the context of when and how the sample was taken rather than as a fixed number.
How it fits with other hormone tests
Prolactin is often considered alongside other markers rather than in isolation. Depending on what a clinician is exploring, it may be paired with reproductive hormones such as estradiol, FSH, or LH, or with thyroid markers, since these systems can interact. Read together, these markers give a clinician more context about the hormonal picture than prolactin alone can provide.
Order online and a physician order is included — no doctor's visit and no insurance needed. Your sample is collected at a Quest Diagnostics patient service center.
Laboratory results should always be interpreted by a licensed clinician who knows your health history. This page is information about a test, not medical advice.
Frequently asked questions
What does a prolactin test measure?
It measures prolactin, a hormone made by the pituitary gland. Prolactin supports milk production and takes part in broader reproductive and hormonal signaling in people of any sex.
Why might prolactin be measured?
Clinicians often use it to help evaluate questions about menstrual cycles, fertility, unexpected milk production, or other symptoms that can be linked to hormonal signaling, usually as part of a broader review.
Can everyday factors affect a prolactin result?
Yes. Prolactin can rise temporarily with things like sleep, stress, or recent activity, so a clinician often takes the circumstances of the draw into account when reviewing the result.
How is the sample collected?
Through a routine blood draw at a patient service center. A phlebotomist takes a small sample from a vein in the arm and sends it to the laboratory.
Is prolactin measured with other hormones?
Often. Clinicians may pair prolactin with reproductive hormones such as estradiol, FSH, or LH, or with thyroid markers, since these systems can interact.
What does a Prolactin test cost without insurance?
$79. Celio Health's price is a flat cash price and insurance is never billed: the required physician's order is included.
Do I need to prepare for this test?
Fast overnight before your blood draw if you can. This is the preparation Quest publishes for this test; if your clinician gives you different instructions, follow theirs.