Pay as you Go

One test kit and supplements
£ 39
One time payment
  • One test kit
  • FREE Personalised Vitamin D Supplements based on your submitted result
  • Minimum of 6 months supply of Vitamin D supplements
  • Dedicated customer care support
  • Next working day delivery

Subscription Plan

Fully managed Vitamin D plan
£ 19
per quarter
  • Test kit every 6 months
  • FREE Personalised Vitamin D Supplements Based on your submitted result​
  • Ongoing supply of Vitamin D supplements
  • Dedicated customer care support​​
  • Next working day delivery​​

Save 10% when you pay for a year upfront

Please see below our frequently asked questions .

No – the NHS does not offer patients routine vitamin D tests.

In the UK, sunlight doesn’t contain enough UVB radiation in winter (October to early March) for our skin to be able to make vitamin D.

During these months, we rely on getting our vitamin D from food sources (including fortified foods) and supplement.


It’s not known exactly how much time is needed in the sun to make enough vitamin D to meet the body’s requirements.

This is because there are a number of factors that can affect how vitamin D is made, such as your skin colour or how much skin you have exposed.

But you should be careful not to burn in the sun, so take care to cover up or protect your skin with sunscreen before your skin starts to turn red or burn.

People with dark skin, such as those of African, African-Caribbean or south Asian origin, will need to spend longer in the sun to produce the same amount of vitamin D as someone with lighter skin.


Vitamin D is the most common nutritional deficiency worldwide. Around one-quarter of the UK population is deficient in vitamin, rising to around one-third in the winter months.


Your Personalised Vitamins (YPV Vitamin D Home Test Kit®) is a test system for the quantitative determination of 25(OH)Vitamin D in finger prick blood samples. The test system is an in-vitro diagnostic device (IVD) intended for home use.

Experts agree that measuring serum 25-hydroxyvitamin D (25[OH]D) is the best indicator of vitamin D status. This is because it reflects cutaneous and dietary sources of vitamin D, has a fairly long half-life (2–3 weeks), and is not subject to tight homeostatic control. As a result, it gives an indication of vitamin D availability over recent weeks

[NICE, 2014; National Osteoporosis Society, 2013; BMJ, 2016; SACN, 2016]. Source:

Our unique programme offers you the ability to maintain your vitamin D at optimal levels throughout the year, by providing you with two home test kits a year and a complete year’s vitamin D supply that is tailored to your personal requirement based on your test results.

Our test kit is the world’s first medical device approved for home use that gives you a quantitative result of your vitamin D levels. It is easy to use, understand and enables you to take more control of your health.

Each time you log your results on your secure personal account at YPV, our unique programme determines your required vitamin dosage level for the following 6 month period. Our systems are designed to identify any unusual trends in your results. If such a trend is highlighted, one of our trained customer care team will contact you to discuss your options.

Your test results show your vitamin D levels and determines your supplement regime.

Gupta AK, Jamwal V, Sakul & Malhotra P (2014) Hypervitaminosis D and systemic manifestations: A comprehensive review. J.Int.Med.Sci.Acad. 27:236-237

Kimball SM, Mirhosseini N & Horlick MF (2017) Evaluation of vitamin D3 intakes up tp 15,000 international units/day and serum 25-hydroxyvitamin D concentrations up to 300 nmol/L on calcium metabolism in a community setting. Dermatoendocrinol. 9:e1300213

Bischoff-Ferrari HA (2014) Optimal serum 25-hydroxyvitamin D levels for multiple health outcomes. In Sunlight, Vitamin D and Skin Cancer (Advances in experimental medicine and biologhy), Reichrath J (ed) pp 500-25. New York: Springer-Verlag

Vitamin D is important for your overall health in several ways. But excess of this vitamin can contribute to several side effects. Source

For an evaluation of the captured image the app needs additional information and instant product data about the rapid test and its specific properties. This data is needed for converting the captured image into a vitamin D concentration present in the blood. The product specific data as well as safety and test functions are provided via the internet. A permanent internet connection is not needed as the app can store the product specific data for two days. The app must just be activated while scanning the product code of the rapid test and being connected to the internet. After that you can use the app for two days without being online.

The APP does not ask for any personal data and NO personal data or readings will become transmitted over the internet. The evaluation will be done exclusively on your smartphone and only you can see the results. No personal data or measurements will be stored so that even malware or investigation systems cannot access your data.

In order to achieve good illumination during the scanning process even in suboptimal lighting situations, the smartphone requires a camera light. This is one of the reasons why the app cannot be used on tablets because those usually do not have a camera light.

The Preventis SmarTest® Vitamin D test system consists of the rapid test immunoassay that detects
25(OH)-vitamin D from whole blood using specific antibodies and an app that quantifies the measurement result.
In a first dilution step the blood is diluted with a dilution buffer and then this diluted sample is applied to the sample application window of the rapid test device.
In a chromatographic step, the diluted sample passes (by capillary forces) through the test matrix together with the gold-labelled antibodies, which later in the presence of vitamin D in whole blood shows the characteristic red colour band at the test line “T”.
As a control for this chromatographic step, the control line “C” indicates that the sample has passed through the entire assay correctly.

Basically, a normal room lighting is optimal for recording. That means you have to avoid too dark rooms as well as direct sunlight. Even a source of light that directly illuminates the rapid test has to be avoided (for example, a table lamp).
Ideal is a room with switched on ceiling lighting or with sufficient light through the windows, whereby the rapid test should not be measured directly at the window.

The bubbles form when you want to apply more than the requested 3 drops of diluted sample by a „soap bubble”
effect. The dilution buffer contains detergent, forming air bubbles at the dropper opening in the absence of liquid
(reservoir is already empty) – on the same principle as soap bubbles.

The camera test is a safety measure indicating that the individual smartphone is capable of evaluating the rapid test according to the specified performance characteristics. The camera test works analogously to a control measurement of a laboratory method. A “sample” (here, schematic image of a high / low sample rapid test) is first measured in the laboratory as a reference and then checked for the matching of the reading from the
individual smartphone and the reference value and rating range.
The camera test is therefore an examination of the device used, but this is not a calibration.

The measurement of a vitamin D level that is too low can have several possible causes:
1. Dosage of insufficient blood in the capillary by trapping air bubbles or incomplete filling
2. Transfer of an insufficient amount of the diluted sample to the rapid test device
3. Diminishing the minimum incubation time of the test (15 minutes)
4. Dilution / contamination of the sample when it is obtained by incompletely dried cleaning solution
5. Insufficient mix of blood sample with the buffer

The measurement of a vitamin D level that is too high can have several possible causes:
1. Faulty level of buffer before dilution of the sample by possibly ejection when piercing with the capillary
2. Exceeding the maximum allowable incubation time of the test by more than 2 minutes
3. Insufficient mix of blood sample with the buffer

The compatibility of the values measured in whole blood with Preventis SmarTest® Vitamin D with the
international gold standard LC / MS in serum is R = 0.875.

r describes the correlation coefficient as a typical value for measurement deviation. It can be between -1 (negative slope \ ) and +1 (positive slope / ),

where ±1 indicates the strongest possible agreement and 0 the strongest possible disagreement. So in our case r=0.88, which displays a very good correlation.

Factors which can cause slight deviation:

– Variation within and between different test methods (i.e. lab Vs convenient rapid test)

– Vitamin D binding protein in samples can bind to Vitamin D and thus falsely reduce the measured values

– Biotin, which is often supplemented, can strongly influence the test results in certain methods

– Abnormal blood haematocrit level

– Time test was taken as Vitamin D level also varies each/within one day

– User technique.

This can have two reasons:
1. Your system has never been supported (it may be too old)
2. The manufacturer of the operating system made an update that has been disseminated without notice.

You can view the supported operating systems and devices at any time here: 

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