TRT with Free Testosterone Blood Test
TRT with Free Testosterone Blood Test
TRT with Free Testosterone Blood Test
TRT with Free Testosterone Blood Test
TRT with Free Testosterone Blood Test, from our experts to you.
Dr Sam Rodgers MBBS, MRCGP

Chief Medical Officer

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Who is a
TRT with free testosterone test for?

Our TRT with Free Testosterone Blood Test profile is for men taking testosterone replacement therapy (TRT) who want to monitor their male and female hormones. Monitoring your hormone levels allows you and your practitioner to optimise your dose of testosterone replacement. This test is also useful if you are experiencing symptoms of low testosterone yet your total testosterone level is normal, and you want to measure your free testosterone as the next step.

What can I learn from
a TRT with free testosterone test?

Our test includes total testosterone and a calculation of the amount of free or unbound testosterone that is available to your tissues. Most testosterone in your body is bound to proteins (sex hormone-binding globulin and albumin) and is unavailable to your cells. By measuring your total testosterone and your levels of SHBG and albumin, the laboratory can calculate your free testosterone level. If you have high levels of SHBG, your free testosterone will be lower, even when your total testosterone is normal.

Why check free testosterone
and female hormones?

Low free testosterone can cause low libido, lack of muscle mass, and low mood. It is also important to check the levels of female hormones in your blood if you are taking TRT. High testosterone levels can also cause high oestradiol, especially if you are experiencing symptoms associated with high oestradiol (including the growth of breast tissue and low libido).

What's Included?

Hormones
Proteins
Select profile for more information
Oestradiol Oestradiol is a female steroid hormone, produced in the ovaries of women and to a much lesser extent in the testes of men. It is the strongest of three oestrogens and is responsible for the female reproductive system as well as the growth of breast tissue and bone thickness. In pre-menopausal women, oestradiol levels vary throughout the monthly cycle, peaking at ovulation. In women, oestradiol levels decline with age, culminating with the menopause when the ovaries stop producing eggs. Low oestradiol can cause many symptoms associated with the menopause, including hot flushes, night sweats and mood swings. Low oestradiol can also cause osteoporosis.
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.
Free testosterone - calc Most testosterone circulating in the blood is bound to proteins, in particular SHBG and albumin; only 2-3 % of testosterone is free and available to cells. This test uses an algorithm to calculate the level of free or unbound testosterone in relation to total testosterone, SHBG and albumin.
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.
Albumin Albumin is a protein which is made mainly in the liver. It helps to exert the osmotic pressure which holds water within the blood. It also helps carry nutrients and medications and other substances through the blood and is important for tissue growth and healing. Albumin also carries hormones around the body, therefore measuring the amount of albumin in the blood can help us calculate how much hormone is available to your tissues.
SHBG SHBG (sex hormone binding globulin) is a protein which transports the sex hormones (testosterone, oestrogen and dihydrotestosterone (DHT)) in the blood.Hormones which are bound to SHBG are inactive which means that they are unavailable to your cells. Measuring the level of SHBG in your blood gives important information about your levels of free or unbound hormones which are biologically active and available for use.

How to prepare
for your test

Special Instructions

Prepare for your TRT with Free Testosterone Blood Test by following these instructions. Please take your sample before 10am. Hormonal contraception can affect this test, taking a break from this and using barrier contraception will give more accurate results. 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. If you are a woman take this test two to five days after the start of your period, ideally on day three. It can be taken any time if you do not have periods.