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Homocysteine (Serum or Plasma)

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

This test measures the amount of homocysteine, a type of amino acid, in your blood. It helps assess risks related to heart disease, nerve damage, or other health conditions.

Quick summary

["Homocysteine levels can indicate potential risks for cardiovascular or neurological issues."]

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

Key facts at a glance

LOINC
13372-8
Short code
(Hcys)2 CSF-mCnc
Synonyms
(Hcys)2 CSF-mCnc
Category
chemistry
Sample
csf
Container
Sterile tube
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Specimen volume
1-2 mL
Stability
Immediate analysis required, Refrigerated: 1h
Hemolysis max
200
TAT
4–24 hours
Order
routine

Why Is This Test Done?

Your healthcare provider may order this test if you have symptoms of conditions like heart disease, nerve problems (neuropathy), or if you have a family history of genetic disorders. It may also be checked as part of routine screening for certain health risks or before certain treatments.

What to Expect Before the Test

No special preparation is usually needed. You may fast for 8–12 hours before the test if instructed, but always follow your provider’s specific instructions. Bring any medications you’re currently taking.

How the Test Is Done

A small needle will draw blood from a vein in your arm. You may feel a slight pinch, but it usually doesn’t cause much discomfort. The blood sample is sent to a lab for analysis.

What the Results Mean

Results are compared to a general reference range, but individual ranges can vary. High levels may signal increased risk for health issues, while low levels are less commonly associated with problems. Your provider will discuss your specific results with you.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Homocysteine Level

Frequently asked questions

What Are Common Questions About This Test?
Will I need to avoid certain foods before the test? Some providers recommend avoiding high-protein foods or supplements (like folate or vitamin B12) for a few days, but always confirm with your provider.
How long will I have to wait for my results? Results are typically available within a few days to a week, depending on lab processing times.
Can high homocysteine levels be lowered? Lifestyle changes like diet (rich in folate, vitamin B6, and B12), exercise, and quitting smoking may help. Your provider may also recommend supplements if needed.
Is this test covered by insurance? Coverage depends on your insurance plan and reason for testing. Check with your provider or insurance company to confirm.
Does this test require fasting? Some providers may require fasting, but always follow their specific instructions to ensure accurate results.
  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