Which blood tests do you need before testosterone is prescribed in Spain?

Before testosterone is prescribed, international guidelines say total testosterone should be measured in the morning (between 07:00 and 11:00) while fasting, and repeated on another day if the result is low. You also need symptoms that fit the picture. On top of that comes a safety check, which usually includes PSA and an assessment of the prostate, along with a full blood count with haematocrit. LH, FSH, prolactin and SHBG are often requested too, to work out where the problem is coming from.

There is one thing you should know from the outset. We have not found a current Spanish protocol, either from SEEN (the Spanish Society of Endocrinology and Nutrition) or from SEMERGEN (the Spanish Society of Primary Care Physicians), that sets out in writing which blood tests are mandatory. What follows is based on the two references used in practice: the Endocrine Society guideline (2018) and the European Association of Urology guideline (EAU, 2026).

Why one low result is not enough

Testosterone levels rise and fall over the course of the day and from one day to the next. They also dip temporarily with poor sleep, acute illness or stress. That is why a single low reading cannot be used to diagnose anything. The Endocrine Society recommends diagnosing male hypogonadism only when there are symptoms and signs of deficiency together with clearly and consistently low levels. The EAU takes the same line. It requires clinical and biochemical criteria together, so a low reading with no symptoms is not enough.

The logical order is this: symptoms first, then the blood tests that confirm or rule them out. If you want to know which symptoms really count, we explain this in the real symptoms of low testosterone and when to worry.

Total testosterone: how, when and how many times

This is the key test. The EAU specifies that it should be measured in the morning, between 07:00 and 11:00, while fasting and using a reliable laboratory method. The Endocrine Society also calls for accurate methods and says the fasting morning measurement should be repeated to confirm the diagnosis.

The EAU is specific about repeat testing. If the result is below 12 nmol/L, at least two measurements on different days are needed before any treatment begins. A sample taken in the afternoon, or after breakfast, can give a lower reading than the true level and lead to the wrong conclusion.

Which levels count as low

The EAU proposes three bands for total testosterone:

• Above 12 nmol/L (3.5 ng/mL): hypogonadism is unlikely.
• Between 8 and 12 nmol/L: a grey zone. The decision depends on your symptoms and on the rest of the work-up.
• Below 8 nmol/L: the level correlates well with sexual symptoms, and there is strong evidence that treatment improves them.

Check the units on your report, because each laboratory may express the result differently. As mentioned above, none of these figures means anything on its own without symptoms.

Free testosterone, SHBG and albumin

Almost all testosterone in the blood is bound to proteins, mainly SHBG and albumin. Only a small fraction circulates freely and acts on the tissues. If SHBG is abnormal, total testosterone can give a misleading picture. For this reason the EAU advises taking SHBG and albumin into account to calculate free testosterone, at least in men with obesity or diabetes. The Endocrine Society also calls for accurate methods to measure free testosterone.

LH, FSH and prolactin: finding the cause

Confirming that testosterone is low is only half the job. The other half is finding out why. If the pituitary hormones (LH and FSH) are high, the problem usually lies in the testicle. If they are low or normal despite low testosterone, the fault lies higher up, and then measuring prolactin matters. Some sources on UK clinical practice include LH, FSH, prolactin and a full blood count in the pre-treatment work-up. They are a useful reference, but they are not an official Spanish standard.

The cause changes the approach. A typical example is someone who has used anabolic steroids and whose hormonal axis has been shut down. We cover this in low testosterone after a cycle of anabolic steroids.

PSA and the prostate before starting

The PSA test is not a box-ticking exercise. The Endocrine Society advises against starting testosterone treatment in men with breast or prostate cancer, a palpable prostate nodule or induration (a hard area felt on examination), or a PSA above 4 ng/mL, or above 3 ng/mL in men at high risk of prostate cancer. Sources on UK practice describe PSA and a digital rectal examination before treatment begins. During follow-up, they suggest referral to a urologist if PSA rises by more than 1.4 ng/mL within a year.

If you want to understand what is checked in the prostate and why, we go into it in PSA and testosterone: what is checked before starting hormone treatment.

Full blood count and haematocrit

Testosterone can increase the production of red blood cells. That is why haematocrit, the proportion of the blood made up of these cells, is checked before and during treatment. The Endocrine Society includes it, together with prostate cancer risk, in the monitoring plan for the first year. One UK source also places it in the pre-treatment work-up and suggests reconsidering treatment if it goes above 54%. We have not been able to confirm the exact threshold the Endocrine Society sets for not starting treatment.

What blood tests don't show but still matters

Two things come up in the consultation that a laboratory cannot measure. The first is fertility. The Endocrine Society advises against starting testosterone treatment in men who want to have children in the near future, because external testosterone suppresses the body's own sperm production. Alternatives for this situation are being studied. We explain them in enclomiphene and clomiphene to raise testosterone without suppressing fertility.

The second is the heart. The TRAVERSE trial (NEJM, 2023) followed 5,246 men aged 45 to 80 with cardiovascular disease or at high cardiovascular risk. Major adverse cardiovascular events occurred in 7.0% of men on testosterone and 7.3% of those on placebo, so it was not shown to increase heart attacks. However, the treated group had more atrial fibrillation, acute kidney injury and pulmonary embolism. So it cannot be called harmless either, and your cardiovascular history forms part of the assessment.

What is known about Spain specifically

There is little confirmed information about Spain. CIMA, the database of the AEMPS (Spanish Agency of Medicines and Medical Devices), contains summaries of product characteristics for testosterone gels authorised in Spain. Beyond that, we have not verified the conditions for prescribing them, whether the National Health System pays for them, or which injectable products are authorised. The European EMAS study, which included a centre in Santiago de Compostela, helps show how common the problem really is. Among 3,369 men aged 40 to 79, late-onset hypogonadism affected 2.1% overall. The rate was 0.1% between 40 and 49, 0.6% between 50 and 59, 3.2% between 60 and 69, and 5.1% between 70 and 79. In other words, it is far less common than many adverts suggest.

This is also why buying testosterone without a prescription is a bad idea: it skips the very work-up that tells apart those who need it from those who don't. We cover this in the risks of buying testosterone without a prescription from online sellers.

Taking the first step sensibly

The key point to remember is that testosterone is prescribed when there are symptoms and low levels confirmed by repeated morning blood tests, and only after checking that the prostate and blood results allow it. In Spain there is now a structured route for this: medical treatment with an assessment beforehand, a prescription only when appropriate from a registered doctor, and ongoing monitoring of your blood tests. This is how AiON runs its men's hormonal health treatment. You can check in a few minutes whether you are eligible for an assessment.