Homocysteine, Total (Serum or Plasma)

Why This Test Might Be Ordered

Your healthcare provider may recommend this test if you have a history of heart disease, stroke, or blood vessel problems. It could also be checked if you have symptoms like fatigue, numbness, or pain in your hands or feet. Sometimes, it’s part of routine screening for people with certain genetic conditions or those taking medications that affect homocysteine levels, such as certain folic acid or vitamin B supplements.

What to Expect Before the Test

You’ll likely have a simple blood draw, usually from a vein in your arm. No special preparation is needed, but tell your provider about any medications you’re taking, especially those that might affect blood levels.

What the Results Mean

High levels of homocysteine may increase your risk for blood clots, heart disease, or nerve damage. Low levels are less concerning but may still warrant discussion with your provider, especially if you have other health conditions.

Common Causes of Abnormal Results

High homocysteine levels can be caused by diet low in vitamins B6, B9 (folate), or B12, kidney disease, certain genetic disorders, or long-term use of some medications. Low levels might be due to over-supplementation with folic acid or vitamin B.