Homocysteine Test-Why am I having this test?

The homocysteine test may be done for several reasons. You may have this test if:

• You are found to have hardening of your coronary arteries but have no other known risk factors for cardiovascular disease.
• You have a strong family history of heart or blood vessel disease at a very young age.
• You have a deficiency of vitamins B6, B12, or folate. In people with these vitamin deficiencies, the homocysteine blood test may be performed to help check for malnutrition.

The test may also be done for an infant or child if there is concern that he or she was born with a condition that causes elevated levels of homocysteine.

What is being tested?

This test measures how much homocysteine is in your blood. Homocysteine is an amino acid that is made when certain proteins are broken down (metabolized). A high level of homocysteine may put you at risk for heart disease and blood vessel disease throughout your body. The test may involve repeated blood tests over 2–24 hours to determine homocysteine levels over time. It may also involve having your blood tested before and after drinking juice that is mixed with another amino acid called methionine.

What kind of sample is taken?

A blood sample is required for this test. It is usually collected by inserting a needle into a blood vessel.

How do I prepare for this test?

Do not eat or drink anything for 10–12 hours before the test, or as directed by your health care provider.

Tell a health care provider about:

• Any medical conditions you have, especially if you have kidney disease. If you have kidney disease, ask if it is safe for you to have this test.
• Whether you have a low intake of B vitamins.
• Whether you smoke.

How are the results reported?

Your test results will be reported as a value that indicates how much homocysteine is in your blood. This will be given as micromoles of homocysteine per liter of blood (μmol/L). Your health care provider will compare your results to normal ranges that were established after testing a large group of people (reference ranges). Reference ranges may vary among labs and hospitals. For this test, common reference ranges are:

• Normal: less than 12 μmol/L.
• Borderline high: 12–15 μmol/L.

Homocysteine levels normally increase with age. Men often have higher homocysteine levels than women.

What do the results mean?

A homocysteine level that is higher than 15 μmol/L may indicate that you have an increased risk for cardiovascular disease, cerebrovascular disease, and peripheral vascular disease. This can increase your risk for:

• Heart attack.
• Stroke.
• Problems with blood flow to the feet and legs. This may cause ulcers or sores that take longer to heal.

High levels of homocysteine may also indicate:

• Vitamin B6 or B12 deficiency.
• Folate deficiency.
• Malnutrition.

Talk with your health care provider about what your results mean.

Questions to ask your health care provider

Ask your health care provider, or the department that is doing the test:

• When will my results be ready?
• How will I get my results?
• What are my treatment options?
• What other tests do I need?
• What are my next steps?

Summary

• A homocysteine test may be done if you are found to have hardening arteries or have symptoms of coronary disease at a very young age. It may also be done to monitor for malnutrition if you have a vitamin B6 or B12 deficiency.
• A high level of homocysteine may put you at increased risk for cardiovascular disease, cerebrovascular disease, and peripheral vascular disease.
• Talk with your health care provider about what your results mean.