Hormone Test

Prolactin Blood Test

Name: Prolactin Blood Test: Normal Range & High | HealthReview
Creator: Suman Konda
Published: 2026-07-05

Prolactin is a hormone produced by the pituitary gland that stimulates breast milk production. Abnormally high levels can cause infertility, irregular periods and vision problems in both men and women.¹

Written by Suman Konda, Clinical Pharmacist · Based on peer-reviewed sources · Editorial policy · Not medical advice

Last reviewed and updated: 26 September 2026 · How we check our content

Quick answer

Normal prolactin is 2 to 29 ng/mL in non-pregnant women and 2 to 18 ng/mL in men; it rises in pregnancy and breastfeeding. A high level outside pregnancy suppresses reproductive hormones, causing missed periods, milky discharge, and infertility in women, and low libido in men. A level above 100 ng/mL suggests a prolactinoma, a pituitary tumour, and needs an MRI.

What is prolactin?

Prolactin is a hormone made by the anterior pituitary gland, located at the base of the brain. Its primary function is to stimulate and maintain breast milk production (lactation) after childbirth. In men and non-pregnant women, prolactin is present in small amounts. Levels naturally rise during pregnancy and breastfeeding. Elevated prolactin (hyperprolactinaemia) outside of pregnancy suppresses reproductive hormones, causing infertility and other symptoms.

Prolactin normal range

Group	Normal Range (ng/mL or mIU/L)
Non-pregnant women	2 – 29 ng/mL
Men	2 – 18 ng/mL
Pregnant women	10 – 209 ng/mL (varies by trimester)
Breastfeeding women	Up to 300 ng/mL

Key points

Normal: 2-29 ng/mL (non-pregnant women), 2-18 ng/mL (men); rises in pregnancy and breastfeeding.
Above 100 ng/mL strongly suggests a prolactinoma (benign pituitary tumour) and needs an MRI.
Common causes of milder rises: medicines (antipsychotics, metoclopramide), hypothyroidism, kidney disease, stress.
Symptoms: irregular or absent periods and milky discharge in women; low libido and erectile problems in men.
Most prolactinomas are treated with cabergoline, which lowers prolactin and shrinks the tumour; surgery is rarely needed.

HIGH Prolactin: Hyperprolactinaemia

Causes: prolactinoma (a benign pituitary tumour that overproduces prolactin, the most common cause of pathological elevation), medications (antipsychotics, metoclopramide, domperidone, some antidepressants, opioids, antihypertensives like methyldopa and verapamil), hypothyroidism (high TRH stimulates prolactin release), kidney disease (reduced clearance), liver cirrhosis, chest wall injury or breast stimulation. Symptoms in women: irregular or absent periods (amenorrhoea), milky nipple discharge (galactorrhoea) unrelated to breastfeeding, infertility, decreased libido. Symptoms in men: reduced libido, erectile dysfunction, infertility, gynecomastia (breast tissue growth). Very large prolactinomas can compress the optic chiasm causing visual field loss.

When is a pituitary MRI needed?

A prolactin level above 100 ng/mL strongly suggests a prolactinoma and warrants a pituitary MRI to look for a tumour. Levels of 25–100 ng/mL can have many causes (medications, hypothyroidism, stress) and are investigated based on clinical context. Very high levels (>500 ng/mL) almost always indicate a large prolactinoma (macroprolactinoma).

Treatment of prolactinoma

Most prolactinomas are treated with dopamine agonist medications, cabergoline or bromocriptine, which are highly effective at lowering prolactin and shrinking the tumour. Surgery is rarely needed. Regular prolactin monitoring is used to track treatment response.

Questions to ask your doctor

Should I have a pituitary MRI?
Is a medication causing my high prolactin?
Should I check my thyroid (TSH)?
Can high prolactin be treated with medication alone?
Will my fertility return once prolactin is normalised?

Prolactin at a glance: causes of raised levels and the numbers

Raised prolactin has many causes — a pituitary tumour is only one of them, and not the commonest. Here are the compiled categories:

Cause category	Examples	Typical pattern
Physiological	Pregnancy, breastfeeding, stress, sleep, chest-wall stimulation	Mild to moderate rise; resolves with the cause
Medicines	Antipsychotics, some antidepressants, metoclopramide, verapamil	Often marked; check the prescription list first
Hypothyroidism	Underactive thyroid raising TRH	Mild rise; TSH is checked with every prolactin
Macroprolactin	Big, inactive prolactin complexes	High number, no symptoms — a lab phenomenon needing confirmation
Prolactinoma	Pituitary adenoma	Persistent marked elevation; imaging follows, not precedes
Typical cost*	&rupee;600–&rupee;1,200; reported in ng/mL (1 ng/mL ≈ 21 mIU/L)

*Prices are approximate bands and vary by city and lab. Check which unit your report uses before comparing numbers.

Prolactin myths vs facts

Raised prolactin triggers immediate tumour fear — usually unnecessarily. Here is what the evidence actually says:

MYTH High prolactin means a pituitary tumour.

Fact: Usually not — medicines (especially antipsychotics), hypothyroidism, stress and macroprolactin are all commoner causes. Tumour is the diagnosis of exclusion after the everyday causes are checked, and imaging follows persistent marked elevation, not every raised value.

MYTH Stress can't raise prolactin.

Fact: It can — mildly. Stress, sleep deprivation, even the stress of the blood draw itself nudge prolactin up, which is one reason borderline values are repeated under calm conditions before any conclusion.

MYTH A borderline result should be acted on immediately.

Fact: Borderline prolactin deserves a repeat — rested, unstressed, not after chest stimulation — before any workup. Single borderline values are the commonest source of unnecessary prolactin anxiety.

MYTH The number is the number, whatever the lab.

Fact: Macroprolactin — large inactive complexes the assay counts as prolactin — produces high values with no symptoms and no disease. Labs can check for it when the number and the patient don't match.

What matters most with your prolactin result

How high, and with what symptoms? Mild elevation without symptoms leans toward stress, medicines or macroprolactin; marked persistent elevation with galactorrhoea or cycle changes leans toward real excess. Number plus story, always.
Bring the medicine list. Antipsychotics and several other common drugs raise prolactin substantially — the prescription history is the first test, and it's free.
Check TSH too. Hypothyroidism raises prolactin via TRH — a raised prolactin with an untested thyroid is an incomplete workup. The two are ordered together for a reason.
Repeat the borderline. Rested, morning, calm — a clean repeat resolves most borderline values without a scan. Imaging is for persistent marked elevation, not first-line. Discuss the full picture with your doctor.

Frequently Asked Questions

Why does my lab's Prolactin range differ from the one shown here?

Every laboratory sets its own reference interval from the analyser, reagents and reference population it uses, so two labs can publish different Prolactin intervals and both be correct, even reporting in the same ng/mL. Read your result against the range printed on your own report.

Should a borderline Prolactin result be repeated?

Usually. Prolactin rises with stress, including the stress of the blood draw itself, recent exercise or sexual activity, and normal night-time sleep, so a single mildly elevated result is often a sampling effect rather than a true abnormality. A borderline Prolactin is normally rechecked rather than acted on.

Is a slightly abnormal Prolactin a reason to worry?

Mildly elevated prolactin is frequently a laboratory artefact rather than a true hormonal abnormality. The stress of the blood draw itself (needle phobia, anxiety in the clinic) reliably raises prolactin, this is called the white-coat effect, as does recent breast examination, vigorous exercise, or eating beforehand. A truly elevated result is confirmed with a repeat fasting, unstressed sample before any imaging or further investigation.

How much does the Prolactin test cost in India?

There is no single fixed price — it varies by city, lab, and whether the test is ordered alone or as part of a panel. NABL-accredited labs usually publish their rates online, so it is worth comparing a couple near you. Whatever you pay, the reference range printed on your own report is what counts — discuss the result with your doctor.

What is a normal prolactin level?

Roughly 2–29 ng/mL for non-pregnant women and 2–18 ng/mL for men; pregnancy and breastfeeding raise it substantially (up to around 209 and 300 ng/mL respectively). Mild elevations just above these ranges are common and usually repeated — go by your own report's range and your doctor's reading.

Can stress raise prolactin?

Yes — physical or emotional stress, poor sleep, and even the blood draw itself can raise prolactin mildly and temporarily. That is why a morning sample taken after sitting calmly is the standard, and why doctors repeat a mildly high value before investigating further.

What is macroprolactin?

Macroprolactin is a large, inactive form of prolactin that standard lab tests still detect — so it can produce a high result in someone with no symptoms and no real excess of active hormone. It is harmless and needs no treatment; labs can confirm it with an extra check if your doctor asks.

Do I need to fast for a prolactin test?

Fasting is not strictly required, but a morning sample is preferred — ideally after restful sleep, avoiding vigorous exercise, chest stimulation, and heavy meals beforehand. Consistent timing makes repeat results comparable.

Pharmacist's practical notes

Drug-induced hyperprolactinaemia is the diagnosis hiding in the prescription list: antipsychotics most prominently, but also metoclopramide, some antidepressants and verapamil. Never stop or switch these over a lab value without the prescriber — but do make sure the prolactin result reaches the prescriber, since alternatives exist.

Macroprolactin is the trap for the unwary: a striking number, a well patient, and a workup launched for a lab phenomenon. When number and patient disagree, ask the lab about macroprolactin before the MRI — it's a blood test, not a scan.

In India

Indian labs usually report prolactin in ng/mL, though some reports give mIU/L instead (roughly, 1 ng/mL equals about 21 mIU/L) — check which unit your report uses before comparing numbers. The test typically costs &rupee;600–&rupee;1,200, though prices vary by city and lab.

Where possible, choose a NABL-accredited lab. A morning, rested sample gives the cleanest baseline.

References

Sources cited on this page. PubMed links open the original abstract.

Melmed S, Casanueva FF, Hoffman AR, et al. Diagnosis and treatment of hyperprolactinemia: an Endocrine Society clinical practice guideline. J Clin Endocrinol Metab. 2011;96(2):273–288. PMID 21296991 · doi:10.1210/jc.2010-1692
Webster J, Piscitelli G, Polli A, Ferrari CI, Ismail I, Scanlon MF; Cabergoline Comparative Study Group. A comparison of cabergoline and bromocriptine in the treatment of hyperprolactinemic amenorrhea. N Engl J Med. 1994;331(14):904–909. PMID 7915824 · doi:10.1056/NEJM199410063311403
Casanueva FF, Molitch ME, Schlechte JA, et al. Guidelines of the Pituitary Society for the Diagnosis and Management of Prolactinomas. Clin Endocrinol (Oxf). 2006;65(2):265–273. PMID 16886971 · doi:10.1111/j.1365-2265.2006.02562.x

What causes a raised prolactin, and when to investigate further

Prolactin is secreted by the pituitary gland and is normally elevated during pregnancy and breastfeeding. Outside of these states, hyperprolactinaemia (raised prolactin) requires investigation. The most important distinction is between physiological/pharmacological causes, which are common, and a pituitary prolactinoma, which is the commonest pituitary tumour and requires specific treatment.

Common pharmacological causes include dopamine antagonists: antipsychotics (haloperidol, risperidone, olanzapine), metoclopramide, domperidone, and many antidepressants. Because dopamine tonically inhibits prolactin secretion, anything that blocks dopamine receptors raises prolactin. In a patient on antipsychotics with a mildly raised prolactin and no symptoms, drug-induced hyperprolactinaemia is the most likely explanation and does not require MRI. However, if prolactin is markedly elevated (>5000 mU/L or >200 ng/mL) or symptoms are prominent, MRI of the pituitary should be performed regardless of medication status.

Macroprolactin, a common false positive

Macroprolactinaemia occurs when prolactin circulates bound to IgG antibodies, forming a large inactive complex. Immunoassays detect these complexes and report a falsely elevated prolactin, even though biologically active prolactin is normal. Macroprolactinaemia is found in approximately 15–25% of patients referred for hyperprolactinaemia and typically causes no symptoms. Most laboratories now screen all elevated prolactin results with polyethylene glycol (PEG) precipitation to detect macroprolactin before further investigation, a normal monomeric prolactin after PEG precipitation rules out clinically significant hyperprolactinaemia.

Treating prolactinomas, dopamine agonists as first-line

Unlike most pituitary tumours, prolactinomas typically shrink dramatically with medical treatment rather than surgery. Dopamine agonists, cabergoline (first choice) or bromocriptine, normalise prolactin in 85–90% of patients and reduce tumour size in most macroprolactinomas (tumours >10 mm). In a double-blind randomised trial of 459 women with hyperprolactinamic amenorrhoea, cabergoline normalised prolactin in 83% versus 59% for bromocriptine, with fewer discontinuations due to side effects (3% vs 12%).² Cabergoline is preferred because of its once- or twice-weekly dosing and lower rate of side effects (nausea, postural hypotension). Pituitary Society guidelines recommend surgery only for dopamine agonist resistance or intolerance, or for emergency decompression when vision is threatened.³

Medical Disclaimer: This page is for general educational purposes only and does not constitute medical advice. Always consult a qualified doctor for diagnosis and treatment decisions.