Vitamin D test kit

A vitamin D test is for checking whether you have the right amount of vitamin D in your body. Vitamin D is an important nutrient for the body, helping it to store calcium, as well as supporting the immune system, and muscle and brain cells.

A vitamin D test uses a sample of your blood to test for the levels of vitamin D present. Specifically, the test checks for levels of 25-hydroxyvitamin D. This is the main form of vitamin D that is found in the blood. It acts as a ‘marker’, which means it can be used to accurately determine the levels of vitamin D in someone’s body.

While symptoms may be able to provide clues that your vitamin D levels are low, the only way to know for sure is to take a blood test. Your GP would recommend a blood test if you have symptoms of low vitamin D or suspect your vitamin levels are low due to risk factors.

Why is it important to know if you have low vitamin D?

Vitamin D is important for a number of functions in the body, particularly bone health. Having low vitamin D levels can lead to a number of health conditions, especially if your levels are low for a long period of time.

Health conditions linked to low levels of vitamin D include:

• bone and muscle conditions, like osteomalacia (soft bones), rickets (bone growth problems in childhood), osteoporosis (weak bones that fracture more easily, and higher risk of falls and muscle weakness in older people
• immune conditions, like multiple sclerosis (where the immune system damages the brain and spinal cord), rheumatoid arthritis (where the immune system damages the joints), and increased risk of catching colds and the flu
• conditions related to circulation and metabolism, like high blood pressure, heart disease, diabetes, and obesity
• mental health conditions, like depression and reduced brain function in older people

Knowing that you have low vitamin D means you can then get treatment and help avoid the health risks that are linked to vitamin D deficiency.

You may want to test your vitamin D levels if you’re experiencing any of the symptoms of low vitamin D or you’re at risk of low vitamin D levels.

Common symptoms of low vitamin D include:

• feeling tired or low energy
• weak muscle and muscle aches or cramps
• bone pain
• lower back pain
• getting sick often
• low mood, depression, or feeling irritable
• cuts or bruises healing slowly
• hair loss
• joint pain
• having trouble walking or balancing
• stress fractures or weak bones

Factors that increase your risk of low vitamin D levels include:

• not going outdoors often
• if you’re living in an institution or care home
• usually covering up your skin when you’re outside
• having darker skin
• not getting enough vitamin D through your diet
• getting older, since your body gets less efficient at making vitamin D
• medical conditions that affect how the body produces vitamin D, like obesity, kidney or liver disease, cystic fibrosis, celiac disease, or Crohn’s disease
• medications that can lower vitamin D levels, like steroids that are taken long term, anti-seizure treatments, HIV treatments, and weight loss medications
• pregnancy or breastfeeding, since your vitamin D needs will be higher than normal

Your full results will be sent to your account but you won’t have to interpret them yourself. We will also send an explanation and advice from one of our doctors.

Our doctors will provide advice on next steps if your results show low vitamin D levels. They will usually recommend treatment with vitamin D supplements or medication. What dose of treatment you need will depend on if you are insufficient (low) or deficient (very low).

Insufficient vitamin D levels mean your levels are low but they can be brought back to normal with regular-dose vitamin D treatment.

Deficient vitamin D levels mean your levels are very low and you will need a higher-dose course of medication to start with to get your levels back up to healthy levels. You can then switch to regular-dose treatment long term.

Treatment for insufficient vitamin D

For insufficient vitamin D levels, tablets containing 1,000 international units (IU) of vitamin D daily should be enough to boost your levels back to normal. This is the same as 25 micrograms (mcg) daily. Asda Online Doctor offers vitamin D tablets that contain cholecalciferol, which is a naturally occurring form of vitamin D.

Treatment for deficient vitamin D

For vitamin D deficiency, you’ll need a higher dose of vitamin D tablets to start with to bring your levels back up to normal. This means taking 10,000IU of vitamin D daily for 8 to 12 weeks then switching to 1,000IU daily after that. You can request a vitamin D starter pack from Asda Online Doctor that includes a supply of 10,000IU and 1,000IU vitamin D.

How accurate is an at-home vitamin D test?

Research shows that test kits that involve finger-prick blood samples like Asda Online Doctor’s vitamin D test kit can be just as accurate as in-person testing that uses blood samples taken using a needle.

Your test results are likely to be accurate as long as you follow the test kit instructions carefully when taking your sample.

When should I take my vitamin D test?

There is no ‘right time’ to take a vitamin D test. Vitamin D levels don’t change much throughout the day or after meals compared to things like blood sugar. This means you can take your test any time, morning or evening, or before or after meals, and still get accurate results.

Can I use the vitamin D test, if I’m already taking vitamin D supplements?

Yes, a vitamin D test can be used even if you’re taking supplements. The test should still be accurate and it can tell you if your current dose of vitamin D supplements are enough to bring your levels back to normal. It can also tell you if your supplements are raising your vitamin D levels too high.

Can you get a vitamin D test with the NHS?

Yes, the NHS offers vitamin D testing. Routine testing isn’t offered, so you will normally only be referred for a test if you make an appointment with your GP and they agree you’re having symptoms of low vitamin D levels.