What is a vitamin D test, how to test it & what does it show? 

Vitamin D is a prohormone (precursor of a hormone) made in our skin, as well as a nutrient found in certain foods. Its main role is to help regulate the amount of phosphate and calcium in the body, which is needed to keep bones, teeth and muscles healthy. There is also some evidence that vitamin D is needed to support immune, brain, cardiovascular, and nervous system health, as well as normal lung functions.

What is a vitamin D test?

A vitamin D test consists of a blood test that helps identify whether you have too much or too little vitamin D. This is achieved by measuring the level of vitamin D in the blood.

The test involves drawing a small sample of blood from a person’s inner arm with a needle and analysing the blood in a laboratory. The process of taking the blood is commonly done a nurse or phlebotomist, and is quick and usually causes only minor discomfort for a short period of time. A blood sample can also be taken with a simple finger prick, which is generally an option taken by those who would prefer to take their own sample from the comfort of their own home.

What does a vitamin D test show?

A vitamin D test measures the level of vitamin D in the blood, which is then compared against a typical ‘normal’ range of vitamin D. Most deficiency in vitamin D is caused by lack of exposure to the sun or insufficient vitamin D in the diet.  However, levels that are lower than normal can be caused by medical conditions including:

  • Gut problems which mean nutrients such as vitamin D are not absorbed as well as is normal such as Coeliac disease and Crohn’s disease.
  • Chronic kidney and liver disease.
  • Patients who have had weight loss surgery. Weight loss surgery entails reducing the size of the stomach and/or bypasses of the small intestines. Patients have to be closely monitored by their doctor post-surgery and will need to take various supplements due to their reduced ability to absorb adequate amounts of nutrients, minerals and vitamins.
  • Drugs such as laxatives, steroids and some antiepileptics.

Your GP may need to undertake further test to determine the cause of low levels and ascertain whether treatment is needed.

How can I check my vitamin D at home?

At Bluecrest, we offer a vitamin D home test kit, which is a low-cost option allowing measurement of  your vitamin D level from the comfort of your own home.

All of our Home Test Kits include:

  • A sample blood collection kit sent straight to your door
  • Results within 8 days of full UKAS accredited laboratory analysis
  • Access to your results through your own secure online MyWellness account
  • 24/7 GP Helpline access

How much vitamin D do I need?

The Department of Health and Social Care (DHSC) recommends that adults in the UK need 10 micrograms (400iu) of vitamin D a day.

During the autumn and winter, we need to get vitamin D from our diet as the sunlight is not strong enough for the body to produce a sufficient amount of vitamin D. However, as it is difficult for people to get enough vitamin D from food alone, the DHSC recommends that everyone aged one and above should consider taking a daily supplement containing 10 micrograms of vitamin D during the autumn and winter.

Most people can get all the vitamin D they need through sunlight on their skin and from a balanced diet between late March/early April to the end of September, so you may choose not to take a vitamin D supplement during these months. However, the DHSC recommends taking a daily supplement of 10 micrograms of vitamin D throughout the year if you are at risk of vitamin D deficiency due to having a dark skin, not going outdoors regularly, and/or covering up most of your skin when outside.

Although it is difficult to get sufficient vitamin D from diet alone, there are certain foods which are a good source of it. Foods high in vitamin D include:

  • Fatty, oily fish like salmon, sardines, mackerel and fresh tuna
  • Egg yolks
  • Liver
  • Red meat
  • Fortified foods, for example foods that have had vitamins or minerals added that weren’t originally in the food. These may include certain spreads, orange juice, and breakfast cereals.

Being on a restricted diet such as a strict vegan diet makes it more challenging to increase vitamin D intake through diet. However, newer food nutrition labels can be used for guidance as they show the amount of vitamin D contained in a particular food item.

How long does a vitamin D test take?

A vitamin D test usually takes less than 5 minutes, as it consists of a simple blood test requiring a small blood sample. There is no specific preparation required, and the person being tested can continue to eat and drink as normal prior to getting tested.

Can low vitamin D levels be dangerous?

It is common for people to be unaware that they are vitamin D deficient until they start experiencing related health problems, particularly since it is not standard medical practice to screen people for vitamin D deficiency.

Over an extended period of time, a lack of vitamin D can lead to complications, such as:

  • Skeletal disorders such as osteomalacia (softening of the bones and osteoporosis (increased bone fragility).
  • Neurological symptoms such as body pains, muscle weakness, and cognitive decline. Although the evidence is not strong some clinical studies have highlighted that low vitamin D levels can lead to an increased risk of diseases of the central nervous system (CNS).

How can I get a vitamin D test?

As it is not standard medical practice to screen people for vitamin D, it can be difficult to get your levels tested unless you suffer from an associated health complications. However, we at Bluecrest offer a range of packages that include vitamin D readings so you can easily find out  your vitamin D level.

At Home

You can test your vitamin D levels from the comfort of your own home with our Total Home Test Kit, which also includes 33 key readings including a full blood count, key blood markers, immunity readings, as well as thyroid, liver and kidney function. All you need to do is order your kit, take your own sample, send it back in our pre-addressed return envelope, and wait to receive your results online within 8 days.

You can also opt for a single vitamin D home test kit, which is a convenient low-cost option that will test your vitamin D levels.

At a clinic

Alternatively, you can book a health check with one of our Certified Healthcare professionals at one of over 2,000 mobile clinics nationwide. We have two packages that include vitamin D measurement:

  • Essential Energy & Fatigue Plus: includes advanced vitamin deficiency checks (including vitamin D), a full blood count, and an advanced thyroid function check to help assess the impact your lifestyle and diet is having on your energy levels.
  • Nutritional Therapy Plan: focuses on an “Eat Yourself Healthy” approach tailored to your health check results. We recommend this plan if you are also struggling with weight management, Irritable Bowel Syndrome, low mood and anxiety, fertility problems or chronic fatigue.