What is being tested?
This test determines the level of homocysteine in the blood. Homocysteine is a sulphur-containing amino acid that is normally present in very small amounts in all cells of the body. Homocysteine is a product of methionine metabolism, and methionine is one of the eleven “essential” amino acids (amino acids that must be derived from the diet since the body cannot produce them). In healthy cells, homocysteine is quickly converted to other products.

Folic acid (folate) is one of the "B" vitamins that is needed to metabolise homocysteine. Vitamin B12, another B vitamin, helps keep folate in its active form, allowing it to keep homocysteine levels low.

How is the sample collected for testing?
A blood sample is taken by needle from a vein in your arm.