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Homocysteine (Serum) Concentration

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

This test measures the level of homocysteine, a type of amino acid found in your blood. It helps assess your risk for certain health conditions.

Quick summary

["Homocysteine levels can indicate risks for heart disease and other vascular problems."]

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

Key facts at a glance

LOINC
27352-4
Short code
(Hcys)2 SerPl-aCnc
Synonyms
(Hcys)2 SerPl-aCnc
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 Is This Test Done?

Your healthcare provider may order this test if you have a history of heart disease, stroke, or other vascular conditions. It may also be used to monitor treatment for conditions like folate or vitamin B12 deficiencies, which can affect homocysteine levels. Sometimes, it’s part of routine screening for people with risk factors for blood vessel problems.

What Does a High or Low Level Mean?

High levels of homocysteine can increase the risk of blood clots, heart disease, or nerve damage. Low levels are less commonly associated with specific health concerns unless caused by a deficiency in certain vitamins.

How Is This Test Performed?

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

What Are Common Causes of Abnormal Results?

Elevated homocysteine levels may be linked to genetics, certain medications, kidney disease, or deficiencies in vitamins like folate, vitamin B6, or vitamin B12. Low levels can sometimes result from overconsumption of certain supplements or specific medical conditions.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance: Homocysteine and Health Risks

Short name

Homocysteine

Frequently asked questions

How often will I need this test?
The frequency depends on your health status, treatment plan, and any risk factors you have. Your healthcare provider will determine how often you need follow-up testing based on your individual situation.
What do I do if my homocysteine levels are high?
If your levels are high, your healthcare provider may recommend lifestyle changes, such as improving your diet (increasing folate, vitamin B6, and vitamin B12), quitting smoking, or managing conditions like diabetes or kidney disease. They may also adjust medications or supplements as needed.
Can I take supplements to lower homocysteine levels?
Supplements like folate, vitamin B6, and vitamin B12 can sometimes help lower homocysteine levels, but it’s important to follow your healthcare provider’s advice. Taking too much of these supplements without guidance can sometimes cause other health issues.
  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