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A homocysteine test measures the amount of the amino acid homocysteine in the blood.

Results are ready in 24 hours.


The normal values listed here—called a reference range—are just a guide. These ranges vary from lab to lab, and your lab may have a different range for what's normal. Your lab report should contain the range your lab uses. Also, your doctor will evaluate your results based on your health and other factors. This means that a value that falls outside the normal values listed here may still be normal for you or your lab.

Homocysteine 1

0.54–2.3 mg/L

4–17 micromoles per liter (mcmol/L)

Many conditions can affect homocysteine levels. Your doctor will discuss any significant abnormal results with you in relation to your symptoms and past health.

High values

High values of homocysteine may be caused by:

  • Not getting enough folic acid, vitamin B6, or vitamin B12 in your diet.
  • Other conditions or diseases, such as homocystinuria, kidney disease, hypothyroidism, Alzheimer's disease, or certain cancers.
  • Using too much alcohol.
  • Your sex. Homocysteine levels are normally higher in men than in women.
  • Age. Homocysteine levels get higher as you get older.

Low values

Low values of homocysteine may be caused by some medicines or vitamins such as daily folic acid, vitamin B12, or niacin.

What Affects the Test

Reasons you may not be able to have the test or why the results may not be helpful include:

  • Going through menopause.
  • Having high blood pressure (hypertension).
  • Smoking or other tobacco use.
  • Having a family history of high homocysteine levels.
  • Drinking more than 2 to 3 cups of coffee a day over many years.
  • Taking medicines, such as anticonvulsants, antibiotics, and birth control pills.
  • Having kidney disease, certain forms of leukemia, or psoriasis.
  • Having a rare family (inherited) disease that causes the lack of an enzyme needed to prevent the buildup of homocysteine in the blood (homocystinuria).

What To Think About

  • A urine test may be done to help detect and monitor homocystinuria. But a blood test is more accurate.
  • Most doctors recommend that you get B vitamins from a balanced diet, and they do not advise that you take vitamin B supplements.

WebMD Medical Reference from Healthwise

Last Updated: March 12, 2014
This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.

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