Homocysteine (serum/plasma mass concentration)
This test measures the amount of homocysteine, an amino acid that can build up in your blood and may increase your risk of certain health problems.
["Homocysteine levels help assess your risk for heart disease and other vascular conditions."]
Key facts at a glance
- LOINC
- 2428-1
- Short code
- Hcys SerPl-mCnc
- Synonyms
- Hcys SerPl-mCnc
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Specimen volume
- 5 mL
- Stability
- Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 4–24 hours
- Order
- routine
Why This Test Is Done
Your healthcare provider may order this test if you have a family history of heart disease, stroke, or blood vessel problems, or if you have symptoms like fatigue, numbness, or swelling in your legs. It’s also used to monitor treatment for conditions like vitamin deficiencies (such as folate or B12) that can affect homocysteine levels.
What to Expect Before the Test
No special preparation is needed, but you may be asked to fast for 8–12 hours before the test if it’s part of a metabolic panel. Bring any medications you’re taking, as they can affect results.
How the Test Is Done
A small needle will draw blood from a vein in your arm. You may feel a brief pinch, but it usually doesn’t cause pain. The blood is sent to a lab for analysis.
What the Results Mean
Results are compared to a general reference range, but individual ranges may vary by lab. High levels may signal increased risk for vascular issues, while low levels could indicate vitamin deficiencies.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Short name
Homocysteine Level
Frequently asked questions
High homocysteine levels are linked to an increased risk of atherosclerosis (plaque buildup in arteries), heart attack, stroke, and peripheral artery disease. It may also raise concerns for conditions like homocystinuria (a rare genetic disorder). Low levels might suggest deficiencies in folate, vitamin B6, or vitamin B12, which can be addressed with diet or supplements.
Elevated homocysteine can be caused by genetic factors, certain medications (like some antidepressants or diuretics), kidney disease, or deficiencies in vitamins B6, B12, or folate. Lifestyle factors like smoking, alcohol use, or poor diet may also play a role.
Yes! Increasing intake of folate-rich foods (leafy greens, beans), vitamin B6 (nuts, whole grains), and vitamin B12 (meat, eggs, fortified foods) may help. Exercise, quitting smoking, and managing conditions like diabetes or kidney disease can also support lower levels.
Sources
- 1
- 2Lab Tests OnlineSource
- 3
Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.
This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy