Serum or plasma concentration of total homocysteine

Why This Test Is Done

Your healthcare provider may order this test if you have risk factors for heart disease, such as high blood pressure, high cholesterol, or a family history of heart problems. It may also be done if you have symptoms like fatigue, numbness, or tingling in your hands or feet. Sometimes, doctors check homocysteine levels in people with genetic conditions like homocystinuria or vitamin deficiencies (like folate or B12).

What to Expect Before the Test

No special preparation is usually needed. You may be asked to fast for 8–12 hours before the test if your provider specifies it. Bring any medications you’re taking, as some (like folic acid or B vitamins) can affect results.

During the Test

A healthcare professional will draw blood from a vein in your arm. You may feel a small pinch, but it usually doesn’t cause pain. The blood sample is sent to a lab for testing.

What the Results Mean

Results are compared to a general reference range, but your actual values may vary based on lab methods. High levels may signal increased risk for heart disease or other health issues, while low levels may indicate deficiencies in certain vitamins.