Homocysteine Test
Reviewed
A homocysteine test measures the amount of homocysteine in a sample of your blood. Homocysteine is an amino acid. Normally, your homocysteine levels are low. High levels of homocysteine in your blood may be a sign that this process is not working right or that you are lacking certain B vitamins. If homocysteine is not broken down, it can build up in your arteries and can not only damage your arteries but also increase your risk of forming blood clots. An increased risk of forming blood clots may increase your risk for heart attack, stroke, and other heart diseases and blood vessel disorders.
Preparation and collection
You may need to fast (not eat or drink) for 8-12 hours before a homocysteine test. Some medicines and supplements may affect your test results. So, tell your provider about all medicines and supplements you take, especially vitamin B. But do not stop taking any medicines unless your provider tells you to.
Understanding this test
Use the reference interval and units printed by the laboratory that performed the test. A result outside that interval is not a diagnosis by itself, and a result inside it does not rule out every condition. Your symptoms, history, medicines, timing, and related tests can change what the result means.
- There is very little risk to having a blood test. You may have slight pain or bruising at the spot where the needle was put in, but most symptoms go away quickly.
- High homocysteine levels do not always mean you have a medical condition that needs treatment. Results may be affected by your age, your sex, and smoking.
- Even though high levels of homocysteine can damage arteries, studies have shown that in most cases lowering homocysteine levels does not reduce the risk of heart attack or stroke.
What to do next
If you have questions about your results, talk with your provider. If you have high homocysteine levels, your provider may suggest that you take vitamin supplements or make changes in the foods you eat. Your provider may also recommend that you take certain vitamins and supplements (known as homocysteine-lowering therapy) if you have homocystinuria or signs of cognitive decline.