Erectile Dysfunction Blood Test, from our experts to you.
Dr Natasha Fernando MBBS, MRCGP

Medical Director

Expert Image

What is
erectile dysfunction?

Erectile dysfunction (or impotence) is when you’re either unable to get an erection or keep an erection for long enough to have sex. Sometimes you might also have a low sex drive (loss of libido).

Occasional ED is very common and is usually nothing to worry about. It’s often caused by a short-term issue such as stress or drinking too much alcohol.

However, for some men, ED can become a long-term problem. This can be very distressing and not only impact your sex life but could also affect your confidence and self-esteem.

What causes
erectile dysfunction?

Our Erectile Dysfunction Blood Test investigates several underlying health conditions that could be contributing to your ED symptoms. These include high cholesterol, diabetes, thyroid conditions, and hormone imbalances.

The good news is that although these physical causes can be serious, they are treatable, and can often be improved by lifestyle changes and/or medication.

What can I learn from an
Erectile Dysfunction Blood Test?

ED has many different causes, and often, several factors could play a part. It could be a sign of an underlying health condition like heart disease, diabetes, or a thyroid condition. ED can also be caused by a hormonal imbalance, such as low testosterone.

Other potential causes include taking certain medications like diuretics and antidepressants, lifestyle factors such as being overweight and smoking, and mental health issues including anxiety and depression. Being over 40 also puts you at higher risk of ED.

What's Included?

Cholesterol status
Thyroid hormones
Select profile for more information

Total cholesterol Cholesterol is an essential fat (lipid) in the body. Although it has a bad reputation it has some important functions, including building cell membranes and producing a number of essential hormones including testosterone and oestradiol. Cholesterol is manufactured in the liver and also comes from the food we eat. Although there are a number of different types of cholesterol, the two main components of total cholesterol are HDL (high density lipoprotein) which is protective against heart disease and LDL (low density lipoprotein) which, in high levels, can contribute to cardiovascular disease. Your total cholesterol result on its own is of limited value in understanding your risk of heart disease; high levels of HDL cholesterol can cause a raised total cholesterol result but may actually be protective against heart disease. Equally, you can have a normal total cholesterol level but have low levels of protective HDL cholesterol. The most important factors are how much HDL and LDL cholesterol you have, and what proportion of your total cholesterol is made up of protective HDL cholesterol. We give a detailed breakdown of the components of your total cholesterol in the rest of this cholesterol profile.
LDL cholesterol LDL cholesterol (low-density lipoprotein) is a molecule made of lipids and proteins which transports cholesterol, triglycerides and other fats to various tissues throughout the body. Too much LDL cholesterol, commonly called 'bad cholesterol', can cause fatty deposits to accumulate inside artery walls, potentially leading to atherosclerosis and heart disease.
Non - HDL cholesterol Your total cholesterol is broken down into 2 main components; HDL (good) cholesterol and LDL (bad). There are more types of harmful cholesterol in your blood than just LDL - these include VLDL (very low-density lipoproteins) and other lipoproteins which are thought to be even more harmful than LDL cholesterol. Non-HDL cholesterol is calculated by subtracting your HDL cholesterol value from your total cholesterol. It therefore includes all the non-protective and potentially harmful cholesterol in your blood, not just LDL. As such, it is considered to be a better marker for cardiovascular risk than total cholesterol and LDL cholesterol. The recommended level of non-HDL cholesterol is below 4 mmol/L.
HDL cholesterol HDL cholesterol (high-density lipoprotein) is a molecule in the body which removes cholesterol from the bloodstream and transports it to the liver where it is broken down and removed from the body in bile. HDL cholesterol is commonly known as 'good cholesterol'.
Total cholesterol : HDL The cholesterol/HDL ratio is calculated by dividing your total cholesterol value by your HDL cholesterol level. It is used as a measure of cardiovascular risk because it gives a good insight into the proportion of your total cholesterol which is good (i.e. high-density lipoprotein HDL). Heart disease risk tools (such as QRisk) use the cholesterol/HDL ratio to calculate your risk of having a heart attack.
Triglycerides Triglycerides are a type of fat (lipid) that circulate in the blood. After you eat, your body converts excess calories (whether from fat or carbohydrates) into triglycerides which are then transported to cells to be stored as fat. Your body then releases triglycerides when required for energy.
HbA1c Haemoglobin A1c (HbA1c), also known as glycated haemoglobin, is a longer term measure of glucose levels in your blood than a simple blood glucose test. Glucose attaches itself to the haemoglobin in your red blood cells, and as your cells live for around 12-16 weeks, it gives us a good indication of the average level of sugar in your blood over a 3 month period.
Testosterone Testosterone is a hormone that causes male characteristics. For men, it helps to regulate sex drive and has a role in controlling bone mass, fat distribution, muscle mass, strength and the production of red blood cells and sperm. Testosterone is produced in the testicles of men and, in much smaller amounts, in the ovaries of women. Testosterone levels in men naturally decline after the age of 30, although lower than normal levels can occur at any age and can cause low libido, erectile dysfunction, difficulty in gaining and maintaining muscle mass and lack of energy. Although women have much lower amounts of testosterone than men, it is important for much the same reasons, playing a role in libido, the distribution of muscle and fat and the formation of red blood cells. All laboratories will slightly differ in the reference ranges they apply because they are based on the population they are testing. The normal range is set so that 95% of men will fall into it. For greater consistency, we use the guidance from the British Society for Sexual Medicine (BSSM) which advises that low testosterone can be diagnosed when testosterone is consistently below the reference range, and that levels below 12 nmol/L could also be considered low, especially in men who also report symptoms of low testosterone or who have low levels of free testosterone.
Prolactin Prolactin is a hormone which is produced in the pituitary gland and plays a role in reproductive health. Its primary purpose is to stimulate milk production after childbirth, and in pregnant and breastfeeding women prolactin levels can soar.
TSH Thyroid stimulating hormone (TSH) is produced in the pituitary gland in order to regulate the production of thyroid hormones thyroxine (T4) and triiodothyronine (T3) by the thyroid gland. If thyroid hormones in the blood are low, then more TSH is produced to stimulate the thyroid gland to produce more of them. If thyroid hormone levels are high, then the pituitary produces less TSH to slow the production of thyroid hormones. If TSH is too high or too low, it normally signifies that there is a problem with the thyroid gland which is causing it to under or over produce thyroid hormones. Sometimes a disorder of the pituitary gland can also cause abnormal TSH levels.

How to prepare
for your test

Special Instructions

Prepare for your Erectile Dysfunction Blood Test by following these instructions. Please take your sample before 10am. Avoid fatty foods for eight hours before your test, you do not need to fast. If you use hormone gels, pessaries, patches, or tablets, we strongly recommend selecting a venous sample to minimise contamination sometimes seen with finger-prick tests. Otherwise, administer any hormone supplements using gloves, and make sure your fingers have not been in contact with hormone supplements for at least four weeks before taking the test. Hormones can be absorbed deep within the skin even after minimal contact and remain there for weeks despite vigorous handwashing. Do not take biotin supplements for two days before this test, discuss this with your doctor if it is prescribed.

Frequently asked questions

What are the symptoms of erectile dysfunction?

You may have ED if you regularly have:

-Trouble getting an erection

-Difficulty maintaining an erection

-Reduced interest in sex

If you have any of these symptoms regularly, you should speak to your doctor to check the underlying cause and see if treatment is required.

How common is erectile dysfunction?
ED is very common, particularly in men over 40 — it’s reported that ED affects up to half of men above this age to some degree.
Can erectile dysfunction be cured?
Most cases of ED are treatable. However, even if your ED cannot be cured, the right treatment may be able to reduce your symptoms. Many options are available, and depending on the cause of your ED, they could include medication, counselling and therapy, and lifestyle changes.
Can I take an erectile dysfunction test at home?
Yes, you can choose to have a nurse visit you at your home to take a blood sample from a vein in your arm (a venous sample). You can also take our blood test for erectile dysfunction at one of our nationwide partner clinics at a time that suits you.

Lifestyle changes to improve ED


Although medication may be the best treatment for some cases of ED, there are still many things you can do that could help to reduce your symptoms. Healthy lifestyle changes can sometimes help, such as losing weight if you’re overweight, stopping smoking, drinking less alcohol, and taking steps to reduce your stress levels. These changes can also help boost your libido (sex drive).  


Can erectile dysfunction be a sign of heart disease?


Trouble getting or keeping an erection may seem like a problem that’s just ‘down there’, but it can be a sign of heart disease. Getting an erection depends on a healthy blood flow, so anything that interferes with that flow can cause problems. 

Atherosclerosis (where your arteries become narrowed, making it difficult for blood to flow through them) accounts for up to half of cases of ED. And high blood pressure is the next most common cardiac cause. 

With cardiovascular disease accounting for most cases of ED, it’s important to check out the underlying causes as soon as possible.


Treatments for erectile dysfunction


If you’re diagnosed with ED, there are many treatment options. For instance, if your ED is caused by high cholesterol, you may be prescribed medications such as statins, which can lower the level of bad cholesterol in your blood.

There are also medications for hormonal imbalances such as testosterone replacement therapy. You can read more about testosterone and men’s health in our Testosterone Hub

Another standard treatment for ED is sildenafil (Viagra), which increases blood flow to the penis. And if your ED is thought to be a side effect of medication, there may be alternatives you can try. 

Therapy such as cognitive behavioural therapy (CBT) or counselling may be recommended if your doctor thinks your ED could be due to a psychological issue.