Homocysteine is an amino acid in the blood. B12, folate and B6 are needed to break it down.
- Normal range (adults)
- 4.4–15.4 µmol/L
- Sample
- Blood
- Fasting
- Not usually needed
- Also called
- Serum Homocysteine, Hcy, Plasma Homocysteine, tHcy
Homocysteine normal range
| Group | µmol/LSame unit in all countries |
|---|---|
| Adults | 4.4–15.4 |
Ranges vary slightly between laboratories. The range printed on your own report is the one to go by.
Why is the Homocysteine test done?
It is checked when B-vitamin deficiency is suspected and sometimes as an extra heart and stroke risk marker.
What does a high Homocysteine level mean?
High homocysteine is linked to higher risk of heart disease, stroke and blood clots, and often signals low B12 or folate.
Common causes
- Low B12, folate or B6
- Kidney disease
- Underactive thyroid
- Smoking
- Genetic variants (MTHFR)
Diet and lifestyle tips
- Eat folate-rich foods: leafy greens, lentils, beans
- Eat B12 foods: meat, fish, eggs, dairy
- Stop smoking
- Check B12 and folate levels with your doctor
When should you see a doctor?
Discuss with your doctor, who may check B12 and folate.
Last updated
This page is for general education and is not a diagnosis. Normal ranges differ between laboratories, so always compare your result with the reference range printed on your own report, and discuss abnormal results with your doctor.