The Driver’s Tiredness Blood Test investigates key markers that may explain reasons for feeling tired, such as anaemia, vitamin deficiencies, or an underactive thyroid.
UK's first direct-to-consumer blood testing service. 
We've delivered over 7.5 million test results. 
We've helped over 200,000 people take control of their health. Biomarker table
Inflammation
hs-CRP
Learn more
C-Reactive Protein (CRP) is an inflammation marker used to assess whether there is inflammation in the body - it does not identify where the inflammation is located. High Sensitivity CRP (CRP-hs) is a test used to detect low-level inflammation thought to damage blood vessels which can lead to a heart attack or stroke. When you suffer a serious injury or infection you experience significant inflammation around the site of injury - such as the swelling around a twisted ankle. Any injury like this will cause your CRP-hs to rise.
Iron status
Ferritin
Learn more
Ferritin is a protein which stores iron in your cells and tissues. Usually, the body incorporates iron into haemoglobin to be transported around the body, but when it has a surplus, it stores the remaining iron in ferritin for later use. Measuring ferritin levels gives us a good indication of the amount of iron stored in your body.
Thyroid hormones
TSH
Learn more
Thyroid stimulating hormone (TSH) is produced in the pituitary gland in order to regulate the production of thyroid hormones thyroxine (T4) and triiodothyronine (T3) by the thyroid gland. If thyroid hormones in the blood are low, then more TSH is produced to stimulate the thyroid gland to produce more of them. If thyroid hormone levels are high, then the pituitary produces less TSH to slow the production of thyroid hormones. If TSH is too high or too low, it normally signifies that there is a problem with the thyroid gland which is causing it to under or over produce thyroid hormones. Sometimes a disorder of the pituitary gland can also cause abnormal TSH levels.
Free thyroxine
Learn more
Thyroxine (T4) is one of two hormones produced by the thyroid gland. It works to speed up the rate of your metabolism. Most T4 is bound to carrier proteins in the blood - it is only the free, or unbound, T4 that is active in the body, which is measured in this test. Free T4 is the less active of the two main thyroid hormones. To have an impact on your cells it needs to convert to the more active T3 when your body needs it.
Vitamins
Vitamin B12 - active
Learn more
Vitamin B12 is important for production of red blood cells which carry oxygen around the body. B12 is also involved in metabolism and the nervous system and prolonged lack of vitamin B12 may cause nerve damage. Although Vitamin B12 is almost entirely found in animal-based foods, many vegetarian and vegan products, especially plant milks are now fortified with Vitamin B12.
Vitamin D
Learn more
Despite its name, vitamin D is actually a hormone that’s produced by your skin when it’s exposed to sunshine. Before your body can use vitamin D produced by sun exposure (known as vitamin D3), it must be converted into another form called 25 hydroxycholecalciferol (25 OH). Vitamin D (25 OH) is the major circulating form of vitamin D, and so your vitamin D (25 OH) level is considered the most accurate indicator of vitamin D supply to your body.
Vitamin D is essential for healthy bones and teeth, as it helps your body absorb calcium. It also plays a role in muscle health, immune function, and mental health.
Low vitamin D symptoms include muscle weakness, mood swings, and fatigue. Many people in the UK have low vitamin D levels, and people with dark skin and people who don’t spend much time outdoors are particularly at risk.
Small amounts of vitamin D can be obtained from food, especially oily fish, eggs, and vitamin-D fortified foods. But if you have a vitamin D deficiency, you’re unlikely to be able to improve your levels by food alone.
Special instructions
How to prepare for your test
Prepare for your Driver's Tiredness Blood Test by following these instructions. Take your sample between 6am and 10am. Take this test when any symptoms of short-term illness have settled. Take your sample at least 24 hours after any vitamin or mineral supplements. Do not take biotin supplements for two days before this test, discuss this with your doctor if it is prescribed. Do not take vitamin B12 for two weeks prior to this test. If your B12 is prescribed ask your doctor whether to stop. If you take thyroxine, you can take your medication as usual, either before or after your blood test. However, if you take desiccated thyroid extract (DTE) or liothyronine, it's best to take it after you've collected your sample. Please let us know in your supporting information if you take amiodarone or lithium as these can affect your thyroid function results.
Blood testing made easy
How it works
Your personalised, actionable health results are only a few clicks away. Order your test, take and post your sample, then view your results online with our doctors' comments.
Your results, simplified
Track, improve, and monitor your health over time
MyMedichecks is your personal online dashboard where you can view your results, access clear and simple explanations about individual health markers, monitor changes in your health, and securely store information about your medical history, lifestyle, and vital statistics.