Vitamins Blood Test

Yes. This test checks the three vitamins that are most commonly deficient in the UK and most likely to explain symptoms: vitamin D, vitamin B12 and folate. Your GP can test them on the NHS if you have symptoms or a risk factor such as a vegan diet, but many people are told their symptoms are too vague to justify testing. A private test gives a definite answer within a week, and a low result can be taken to your GP for treatment.

Vitamin D appears as 25-hydroxyvitamin D, written 25(OH)D or 25-OH vitamin D, measured in nanomoles per litre (nmol/L). That is the storage form of the vitamin and the one that reflects your overall status. It is what this test measures and what your report will show.

Most people in the UK are below 50 nmol/L by the end of winter, because the sun is too weak from October to March to make vitamin D in the skin. The NHS advises everyone to consider a 10 microgram daily supplement through autumn and winter. These thresholds are kept under review and may be adjusted; your GP report uses the guidance current at the time of your test.

It is called a serum vitamin B12 test, sometimes labelled cobalamin, and it is measured in nanograms per litre (ng/L) or picomoles per litre (pmol/L). It shows the total amount of B12 in your blood. Results below the reference range, or at the low end with symptoms, indicate deficiency. Your GP may follow a borderline result with an active B12 or a test for the antibodies behind pernicious anaemia.

Vitamin D deficiency causes tiredness, bone and muscle aches, low mood and, when severe, bone softening. Vitamin B12 deficiency causes extreme tiredness, breathlessness, pins and needles, a sore red tongue, mouth ulcers, poor memory and low mood, and can damage nerves if left untreated. Folate deficiency causes similar tiredness and anaemia. All three are common in vegans and vegetarians (B12 especially), older people, those on metformin or acid-reducing medication, people with gut conditions, and anyone with little sun exposure or darker skin (vitamin D).

With the home kit: a small finger-prick sample that you post back to the laboratory in the packaging provided. It measures vitamin D, B12 and folate with the same laboratory analysis as the clinic test and comes with the same GP report. There is no reliable way to check vitamin D without a blood test; symptoms alone are too general.

Yes, when there is a reason to. A GP can test vitamin D if you have bone pain, muscle weakness or a risk factor, and B12 and folate if you have symptoms of anaemia or nerve problems or are on a restricted diet. Routine testing of people without symptoms is not offered, which is why many people choose a private test to find out where they stand or to check whether a supplement is working.

With a standard daily supplement of 10 to 25 micrograms (400 to 1,000 IU), levels rise slowly over two to three months. For deficiency below 25 nmol/L, GPs often prescribe a higher loading dose for six to eight weeks, then a maintenance dose. A repeat test three months after starting shows whether you have reached a sufficient level. B12 deficiency is usually treated with injections if absorption is the problem, or high-dose tablets if diet is.

A private vitamin deficiency blood test costs from £69 at Goodbody Clinic. The home finger-prick kit is £69, a blood draw at one of our clinics is £109 and a nurse home visit is £129. Every option includes laboratory analysis of vitamin D, B12 and folate and a GP report. For a wider panel covering vitamins A, E and the B group, see the Advanced Vitamins Blood Test.

Order the home kit online, book a blood draw at one of Goodbody's 250+ partner clinics across the UK, or arrange a nurse home visit. No GP referral is needed. Find your nearest clinic.