High prolactin assessment

First line

Blood test to investigate high prolactin with single prolactin, pooled prolactin, macroprolactin, beta-hCG, TSH, testosterone and oestradiol. It checks whether the rise persists at rest, whether it corresponds to a form with little biological activity and whether there is a hormonal cause that helps explain it.

No prescription or appointment needed

Results in 1-2 working days

Includes: Prolactin · Pooled prolactin · Macroprolactin · Beta-hCG · TSH · Total testosterone · Oestradiol. See what each one measures

What it is for

It is used to confirm and put into context hyperprolactinaemia found in a previous blood test. High prolactin can be due to stress, pregnancy, some medicines, hypothyroidism, a macroprolactin form or a pituitary disorder. Separating these possibilities avoids interpreting a single figure as a diagnosis.

The profile does not include an MRI scan and does not automatically determine the cause. If monomeric prolactin remains raised and the result fits the symptoms, the medical assessment decides whether medicines need reviewing, the test needs repeating or the pituitary gland needs investigating.

When it is recommended

High prolactin in a previous blood test
Absent or irregular periods, or milk discharge outside breastfeeding
Loss of sexual desire, erectile dysfunction or low testosterone
Difficulty getting pregnant together with a suspected hormonal cause
Headache or visual disturbances accompanied by other compatible findings, a situation that requires medical assessment

Clinical comment

Prolactin responds easily to stress, exercise, sleep and breast stimulation. That is why we have included a pool after resting, which helps show whether the rise persists once the effect of the moment has faded.

Macroprolactin is just as important. It can raise total prolactin without producing the usual effects of the hormone. Identifying it avoids starting pituitary investigations or treatments based on a figure that does not properly reflect biological activity. Even so, the reading should focus on the monomeric prolactin reported by the laboratory.

Bear in mind that many medicines raise prolactin, including some antipsychotics, antidepressants, antiemetics and opioids. They must not be stopped on your own. Beta-hCG, TSH and the sex hormones complete the context, but a pituitary cause is only considered after confirming that the rise is real and persistent.

Dr. Antonio Mas

What is tested

Prolactin: Measures the concentration of the hormone in an initial sample.
Pooled prolactin: Averages several samples taken after a period of rest to reduce the effect of the stress of the blood draw.
Macroprolactin: Detects a form of prolactin bound to immunoglobulins that can raise the total figure while having little biological activity.
Beta-hCG: Shows whether there is a pregnancy when one is possible, and provides information in other, less common situations.
TSH: Helps assess whether there is hypothyroidism, which can raise prolactin.
Total testosterone: Assesses the effect of raised prolactin on the male gonadal axis.
Oestradiol: Provides information on the female gonadal axis and is interpreted according to sex, age and the point in the cycle.

How to prepare

Have the sample taken in the morning, fasting. Arrive in good time so you can stay at rest before and during the pooled samples. Avoid intense exercise, sexual activity and breast stimulation during the previous 24 hours. Report all the medication you take and do not stop any medicine without medical advice.

You can add

Without another needle. It is offered when you order, so you do not have to decide now.

General blood testA general blood test with full blood count, glucose, cholesterol and kidney and liver function: the basic parameters included in any general check-up.+€59.00
General + nutritional blood testEverything in the general blood test (anaemia, kidneys, liver, cholesterol and glucose) plus iron stores, vitamin D, vitamin B12 and folic acid. It is the broadest add-on: it covers the general and the nutritional in one go.+€129.00
Thyroid functionBrings together TSH and free T4, the two basic tests for assessing how the thyroid is working.+€29.00

Related blood tests

We have other profiles in Other tests with more or fewer tests:

The most comprehensive is not always the most useful. This is the one we recommend to start with; the others cover specific situations.

What it is based on

Endocrine Society · J Clin Endocrinol Metab 96(2):273-288
Diagnosis and Treatment of Hyperprolactinemia: An Endocrine Society Clinical Practice Guideline
Recommends measuring macroprolactin when prolactin is high without symptoms, because macroprolactinaemia is a common cause of that finding and recognising it avoids imaging tests that will add nothing. It also asks for medicines, kidney function and hypothyroidism to be reviewed first, which is the job done here by TSH and the medical history. On the pool it is worth being precise: the guideline considers a single measurement sufficient and reserves repeated sampling every 15 or 20 minutes for doubtful cases. Here it is always done because it costs the same.
Pituitary Society · Nat Rev Endocrinol 19(12):722-740 · PMID 37670148 · doi 10.1038/s41574-023-00886-5
Diagnosis and management of prolactin-secreting pituitary adenomas: a Pituitary Society international Consensus Statement
This is the current consensus, published after the 2011 guideline, and it has been read in its PDF, which is open access (checked on 5/9/2026). It supports three decisions in this profile that previously rested only on practice. One: repeating the measurement when prolactin is high but below five times the upper limit, and taking it through an indwelling cannula if the stress of the needle is suspected (strong recommendation); this is what pooled prolactin does. Two: measuring macroprolactin when the rise is moderate, below 200 ng/ml, at least if the clinical picture does not fit (strong). Three: recognising primary hypothyroidism, kidney failure and liver failure as causes of moderately high prolactin, and not forgetting pregnancy (strong); hence TSH and beta-hCG. It adds something the profile page cannot resolve but is worth knowing: with a very large adenoma and prolactin that is only slightly high, the sample must be repeated at a 1:100 dilution because of the immunoassay hook effect, and that is decided in a consultation, with the imaging in front of you.

Protocol designed by Dr. Antonio Mas, specialist in Endocrinology and Nutrition, Spanish medical licence no. 080846289, and reviewed in September 2026.

This blood test is a standardised protocol and does not replace a medical consultation. If you have symptoms, a known condition or a complex clinical situation, speak to your doctor.