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Homocysteine, Serum

Published: August 9, 2026Updated: August 16, 2026

This test measures the level of homocysteine, a type of amino acid (a building block of proteins) found in your blood.

Quick summary

["Homocysteine levels can help assess your risk for certain health conditions, including heart disease and nerve damage."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
50050-4
Short code
Hemicystine SFr Amn
Synonyms
Hemicystine SFr Amn
Category
chemistry
Sample
fluid
Container
Sterile tube
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Specimen volume
2-5 mL
Stability
Room temperature: 2h, Refrigerated: 24h
Hemolysis max
300
TAT
4–24 hours
Order
routine

Why Might This Test Be Done?

Your healthcare provider may order this test if you have a family history of heart disease, stroke, or nerve problems, or if you have conditions like kidney disease, certain vitamin deficiencies, or a history of blood clots. It may also be checked if you’re taking medications that affect homocysteine levels, such as certain blood thinners or folic acid supplements.

What Does a High or Low Level Mean?

High levels of homocysteine may increase your risk for cardiovascular issues, such as atherosclerosis (plaque buildup in arteries), or nerve damage. Low levels are less commonly associated with specific health concerns but may indicate normal metabolic function.

How Is This Test Performed?

A small sample of your blood is drawn from a vein, usually in your arm. The blood is then sent to a lab for analysis using a specialized immunoassay method to measure homocysteine concentration.

What Should You Do Before the Test?

No special preparation is usually needed, but you may be asked to fast for 8–12 hours before the test if instructed by your provider. Avoid smoking or consuming alcohol for a few hours beforehand.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance: Homocysteine plays a role in blood vessel health and nerve function. Elevated levels are linked to an increased risk of vascular diseases, including heart attacks and strokes, and may also affect cognitive function over time. Regular monitoring can help manage risk factors in patients with conditions like diabetes, kidney disease, or genetic predispositions.

Short name

Homocysteine

Frequently asked questions

What causes elevated homocysteine levels?
Elevated homocysteine can be caused by genetic factors, certain medications (like blood thinners), kidney disease, vitamin deficiencies (such as folate or vitamin B12), or conditions like diabetes. Lifestyle factors, such as smoking or poor diet, may also contribute.
How long does it take to get results?
Results are typically available within 1–3 business days, depending on your lab’s processing time. Your healthcare provider will discuss the results with you during your follow-up visit.
Can I lower my homocysteine levels naturally?
Yes! Increasing your intake of folate (found in leafy greens, beans, and fortified foods), vitamin B6 (found in nuts, seeds, and whole grains), and vitamin B12 (found in meat, eggs, and dairy) may help. Lifestyle changes like quitting smoking, managing stress, and maintaining a balanced diet can also support healthy homocysteine levels.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

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.

Medical Disclaimer

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