Overview of Homocysteine
What is Homocysteine?
Why is Homocysteine done?
The Homocysteine Test is performed:
- To screen for heart attack and stroke, especially in people with no risk factors but with a family history of cardiovascular diseases
To detect and diagnose an inherited disease called homocystinuria in newborns and infants
- To detect deficiency of Vitamin B6, B12, or Folic acid
What does Homocysteine Measure?
Homocysteine is an amino acid which is an intermediate in the production of cysteine from methionine. Methionine is obtained from dietary sources, mainly fish, meat, and dairy products, and is converted to homocysteine, and then to cysteine in the body. This conversion from methionine to cysteine is regulated by various enzymes which require Vitamin B6, B12, and folic acid to work. Deficiency of these vitamins causes an increase in the levels of homocysteine in the body. Increased homocysteine levels in the blood can be due to a rare genetic disease called homocystinuria, where the enzymes needed for methionine metabolism are dysfunctional.
Increased levels of homocysteine in the blood are associated with an increased risk of cardiovascular diseases including atherosclerosis, thrombosis (formation of blood clots) in blood vessels, heart attack, and stroke. It has also been implicated in some studies with an increased risk of Alzheimer’s disease.
Preparation for Homocysteine
- Do not eat or drink anything other than water for 8-12 hours before the test.
Sample Type for Homocysteine
Interpreting Homocysteine results
Normal homocysteine levels: 4 to 15 µmol/L
Concentrations above 15µmol/L are considered increased homocysteine level. Increased level of homocysteine in the blood is called Hyperhomocysteinemia, which is classified into:
· Moderate hyperhomocysteinemia: 15 to 30 µmol/L
· Intermediate hyperhomocysteinemia: 30 to 100 µmol/L
· Severe hyperhomocysteinemia: More than 100 µmol/L
Hyperhomocysteinemia can be caused due to:
· Deficiency of Vitamin B6, B12, or Folic acid
· Inherited disease homocystinuria (Genetic abnormality of methionine metabolizing enzymes)
· Chronic alcoholism
The normal level of homocysteine in the blood is usually higher in males than in females. Homocysteine levels also increase with age.
Answers to Patient Concerns & Frequently Asked Questions (FAQs) about Homocysteine
Frequently Asked Questions about Homocysteine