Testosterone, oestrogen and dihydrotestosterone are all bound to sex hormone binding globulin (SHBG) which means that they are unavailable to your cells. Measuring the levels of SHBG in the blood gives important information about your levels of free or unbound hormones which are biologically active and available for use.

Prolactin is a hormone which is made in the pituitary gland and plays a role in reproductive health. Its main purpose is to stimulate milk production after birth and in pregnant and breastfeeding women prolactin levels will soar.

Raised levels in a woman who is neither pregnant or breastfeeding can signal fertility problems as well as irregular periods.

Higher levels in men can cause reduced sex drive, erectile dysfunction, and lack of energy and fertility problems.

The Majority of testosterone circulating within the blood is bound to proteins, in particular SHBG and albumin only 2-3% of testosterone is free and available to cells. The test uses an algorithm to calculate the level of free or unbound testosterone in relation to total testosterone, SHBG and albumin.

A lower level in a male could lead to symptoms which include low libido, erectile dysfunction, depression and a difficulty in gaining muscle mass.

In women an increased level could be an indication of polycystic ovary syndrome.

Follicle Stimulating Hormone 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. Levels of FSH rise in women as egg production declines, therefore raised FSH often coincides with the onset of the menopause and is a measure of ovarian reserve.

Elevated FSH in women indicates reduced egg supply whereas low levels can signal that you are not ovulating or are pregnant.

Levels of FSH in men rise with age, but can also indicate testicular damage and reduced sperm production. Low levels of FSH are detected when men are not producing sperm.

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.

Raised LH in women can signal that you are not ovulating, that you are menopausal or that your hormones are not in balance (as with polycystic ovaries).

Raised LH in men can signal that the testes are not producing enough testosterone.

Oestradiol is a steroid hormone that accounts for 80% of the oestrogen in the female body. It is secreted by the ovaries and is responsible for the development and maintenance of reproductive structures, including fat distribution, preparing the follicle in the ovary for the release of an egg and helping to maintain bone density. This blood test measures the level of oestradiol in your body.

A free androgen index (FAI) is a ratio figured out after a blood test for testosterone.

It’s used to see whether you have abnormal androgen levels. …

A free androgen index measures testosterone in your blood and compares it with the total amount of testosterone and SHBG in your body.

Thyroid Stimulating Hormone is produced in the pituitary gland and stimulates the thyroid gland to produce thyroid hormones thyroxine (T4) and triiodothyronine (T3).

High levels of TSH indicate an underactive thyroid while low levels indicate an overactive thyroid. In primary pituitary failure, a low TSH will be associated with an underactive thyroid.

Thyroxine (T4) is one of two hormones produced by the thyroid gland. Most T4 is bound to carrier proteins in the blood – this test measures the level of T4 which is free, or unbound, circulating in your blood.

High levels of free thyroxine can indicate an overactive thyroid while low levels can indicate an underactive thyroid.

Low cortisol levels can also cause anxiety, irritability, inability to handle stress, fatigue and a feeling of being overwhelmed

they can also point toward problems with your adrenal glands.