*Welcome to the OutUK series looking at gay men and their health brought to you in association with the NHS* website.**
	Each week we'll tackle a different topic in our A to Z of Gay Health. We'll have features and advice on everything from relationships, sexual health, mental and physical conditions and how to stay fit. You can follow any of links provided below for more information direct from the NHS website, or see this week's feature L: Laxatives.

Diagnosis

See a GP if you think you may have an overactive thyroid (hyperthyroidism).

A diagnosis will be based on your symptoms and the results of a blood test that assesses how well your thyroid is working.

Thyroid function blood test

A GP may arrange for you to have a blood test to check your thyroid hormone levels. This is known as a thyroid function test.

The test checks the levels of:

thyroid-stimulating hormone (TSH) - a hormone produced by the pituitary gland (a gland at the base of the brain) which controls the production of thyroid hormones
triiodothyronine (T3) - one of the main thyroid hormones
thyroxine (T4) - another of the main thyroid hormones

Your thyroid hormone levels will be compared to what's normal for a healthy person of your age. A low level of TSH and high levels of T3 and/or T4 usually means you have an overactive thyroid.

Doctors may refer to these measurements as "free" T3 and T4 (FT3 and FT4).

What's considered normal varies depending on things such as your age and the exact testing technique used by the laboratory.

Find out more about thyroid function tests on the Lab Tests Online UK website

Further tests

If your thyroid hormone levels are high, you may be referred to a specialist for further tests to find out what's causing it.

Further blood tests

You may have another blood test to look for anti-thyroid antibodies.

These are usually found if you have Graves' disease, a common cause of an overactive thyroid.

A blood test called erythrocyte sedimentation rate (ESR) may also be done to check for inflammation in your body.

If there are signs of inflammation, the increase in thyroid hormones is caused by thyroiditis (inflammation of the thyroid).

Find out more about ESR tests on the Lab Tests Online UK website

Thyroid scan

A thyroid scan may be used to look for problems such as lumps (nodules) on your thyroid.

You'll be asked to swallow a small amount of a slightly radioactive substance that will be absorbed by your thyroid. It can also be given by injection.

A scan is then done to see how much of the substance has been absorbed and to examine the size and shape of your thyroid.

OutUK's A to Z of Gay Health continues and you can read this week's feature L: Laxatives. We have covered many subjects in this series and you can catch up with all of our Previous A to Z Features. If you want to find out more about this particular topic you can visit the Original article on the NHS website. If you are worried by any aspect of your health make sure you go and see your doctor or book an appointment at your local clinic.
Photos: LightFieldStudios and one of VladOrlov, Stockcube, darak77, ajr_images or rawpixel.com.