A homocysteine test measures the amount of homocysteine in your blood. Homocysteine is a

type of amino acid, a chemical your body uses to make proteins. Normally, Vitamin

B12,Vitamin B6  and foloic acid break down homocysteine and change it into other

substances your body needs. There should be very little homocysteine left in the

bloodstream. If you have high levels of homocysteine in your blood, it may be a sign of a

vitamin deficiency, heart disease, or a rare inherited disorder.