Testosterone
Testosterone is a hormone that causes male characteristics. For men, it helps to:
Regulate sex drive
Control bone mass
Distribute fat
Support muscle mass and strength
Produce 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
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
Distribution of muscle and fat
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.
FSH
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 men, FSH acts on the seminiferous tubules of the testicles where they stimulate immature sperm cells to develop into mature sperm.
LH
Luteinising Hormone (LH) is produced by the pituitary gland and is important for male and female fertility. In men it stimulates the production of testosterone.
Oestradiol
Oestradiol is a female steroid hormone, produced in the ovaries of women and to a much lesser extent in the testes of men. Low oestradiol can cause osteoporosis.
Free androgen index
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.
Prolactin
Prolactin is a hormone which is produced in the pituitary gland and plays a role in reproductive health.
Adrenal Hormones:
DHEA Sulphate
DHEAS is the sulphated form of DHEA, a hormone which is produced by the adrenal glands and is responsible for male characteristics in both men and women. DHEAS gradually declines from the age of 30 onwards.
Proteins:
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.
