Vitamin D & B12 Blood Test
2 Biomarkers | Venous or Capillary Blood Test | CE-marked | UKAS-accredited | Doctor-reviewed results with personalised interpretation.
A focused vitamin check measuring total vitamin B12 and vitamin D. Designed for people checking common vitamin markers linked to energy and wellbeing, this test gives clear, clinically reviewed insight so you can understand your results and know what to do next.
Results are typically available within 2 working days from when your sample reaches the laboratory (excluding weekends and bank holidays).
Vitamins & Nutritional Status
- Total Vitamin B12
- Vitamin D
How to prepare
- Fasting required 8–12 h before the test (water only) recommended for glucose, cholesterol/triglyceride accuracy
- Sample timing: between 7:00 AM – 10:00 AM
- Stay hydrated; avoid strenuous exercise, heavy meals, and supplements (iron, B12, multivitamins, biotin) for 48 hours prior
- Continue prescribed medications unless otherwise directed
Frequently asked questions
Who is this test for?
It is a straightforward check of two of the most commonly deficient nutrients in the UK. It suits people with fatigue, low mood, pins and needles, or anyone on a plant-based diet or getting limited sunlight.
Do I need to fast or test at a particular time?
No. Neither vitamin D nor B12 requires fasting, and neither varies meaningfully through the day, so you can test whenever is convenient.
I already supplement. Should I still test?
Testing is arguably more useful if you supplement, as it shows whether your current dose is achieving an adequate level. Bear in mind that recent oral B12 raises the measured value, so pausing for one to two weeks gives a truer reading if you want to know your baseline.
What are the symptoms of B12 deficiency?
Fatigue, pins and needles or numbness in the hands and feet, mouth ulcers, poor balance, memory difficulties and low mood. Neurological symptoms can develop before anaemia appears, which is why deficiency should not be excluded on a full blood count alone.
Do I need vitamin D all year round?
UK public health guidance suggests considering a daily supplement of 10 micrograms during autumn and winter, when sunlight is insufficient for skin production. Those with limited sun exposure, darker skin, or who cover up may benefit year round. Testing shows what your level actually is.