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Hormones
FSH
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Follicle Stimulating Hormone (FSH) is produced in the pituitary gland and is important for women in the production of eggs by the ovaries and for men in the production of sperm. In the first half of the menstrual cycle in women, FSH stimulates the enlargement of follicles within the ovaries. Each of these follicles will help to increase oestradiol levels. One follicle will become dominant and will be released by the ovary (ovulation), after which follicle stimulating hormone levels drop during the second half of the menstrual cycle. In men, FSH acts on the seminiferous tubules of the testicles where they stimulate immature sperm cells to develop into mature sperm.
LH
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Luteinising Hormone (LH) is produced by the pituitary gland and is important for male and female fertility. In women it governs the menstrual cycle, peaking before ovulation. In men it stimulates the production of testosterone.
Testosterone
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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 androgen index
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The free androgen index (FAI) is a calculation used to determine the amount of testosterone which is free (unbound) in the bloodstream. Most testosterone is bound to proteins sex hormone binding globulin and albumin and is not available to interact with the body's cells. The FAI is a calculation based on the ratio of testosterone and SHBG and is a measure of the amount of testosterone that is available to act on the body's tissues. The free androgen index is used in women to assess the likelihood of polycystic ovarian syndrome. In men, free testosterone gives a better indication of testosterone status.
Proteins
SHBG
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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.
If you have periods
Tests with LH, FSH, or oestradiol
If you're taking your test to learn more about your fertility, take your test between days 2 and 5 of your menstrual cycle, or ideally day 3. Otherwise, for a general health check or if you're postmenopausal, you can take your test at any time.
In either case, it's important to log the date of your last period, and any other information regarding your periods or menopause status, in your MyMedichecks account right after taking your sample.
If you don't let us know the date of your last period, we'll interpret your result as though you took your test on day 3.
Special instructions
How to prepare for your test
Prepare for your Polycystic Ovary Syndrome Blood Test by following these instructions. Take your sample between 6am and 10am. 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. Avoid taking a finger-prick sample from a finger used to apply hormone gels/pessaries/patches in the past 4 weeks. Use gloves to apply these. Do not take biotin supplements for two days before this test, discuss this with your doctor if it is prescribed. Hormonal contraception can affect the results of this test. Taking a break from this and waiting for your periods to restart before your blood test will give more accurate results.
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FAQs
What is a PCOS Blood Test?
Our Polycystic Ovary Syndrome Blood Test includes tests for testosterone, sex hormone binding globulin (SHBG), and the free androgen index (FAI) to indicate the number of available androgens circulating in the blood. You can also measure your luteinising hormone (LH) and follicle-stimulating hormone (FSH). A high LH/FSH ratio of between 2:1 or more may indicate PCOS.
Who is a PCOS Blood Test for?
Our PCOS Blood Test is for any woman experiencing PCOS symptoms who wants to investigate further.
What is PCOS?
Polycystic Ovary Syndrome (PCOS) is a condition in women that affects the ovaries - resulting in the development of cysts on the ovaries, which can become enlarged. PCOS is a common condition and, in the UK, affects around seven in every 100 women. Initial investigations into PCOS focus on medical history, irregular periods (or none at all), and high levels of male hormones (androgens) in the body.