Vitamin B12 is an essential vitamin found in meat products and certain algae such as seaweed. It helps maintain healthy nerve cells and red blood cells and is also needed to make DNA, the genetic material in all cells. Both high and low vitamin B12 blood test levels may indicate an underlying problem. Low levels can suggest anaemia, a parasite or hyperthyroidism, whilst high levels can be a sign of liver disease, diabetes or kidney failure.

Vitamin D is essential for bone strength as it helps the intestines absorb calcium. Calcium and vitamin D play a critical role in developing and maintaining your overall bone health, and when you don’t get enough you increase your risk of developing osteoporosis and the incidence of stress fractures.

This simple iron test measures how much iron you have in your blood, as well as the amount of iron you have stored in your body. This iron test can be used to diagnose anaemia or monitor an existing iron deficiency. This iron test can also be used to investigate iron overload syndrome (haemochromatosis) which is an inherited condition where your body cannot remove excess iron.