Vitamin B9 (also known as folate) is essential for DNA production and the development of red blood cells. A lack of folate can cause anaemia, increase your risk of heart disease and bowel cancer. It can increase your risk of infertility. 

Vitamin B12 is a vitamin which is necessary for the formation of red blood cells, tissue and cellular repairs and nerve health. It can be found in animal products such as poultry, milk and eggs. Vitamin B12 tests are used to help diagnose the cause of anaemia.

Vitamin D is a vitamin which is used in the regulation of calcium and magnesium absorption from the gut, it is also important for the growth and health of bones. Vitamin D comes from two sources; it can be ingested from foods and supplements or be produced in the skin once it is exposed to sunlight. Vitamin D tests are used to identify vitamin D deficiency and to monitor disease that interfere with fat absorption like Crohn’s disease.