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Serum or plasma mass concentration of homocysteine

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

This test measures the amount of homocysteine, an amino acid, in your blood. High levels may indicate an increased risk of certain health conditions.

Quick summary

["Homocysteine levels can help assess your risk for heart disease or other vascular problems."]

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

Key facts at a glance

LOINC
43281-5
Short code
HDV Ag Ser-mCnc
Synonyms
HDV Ag Ser-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 Might Be Ordered

Your healthcare provider may recommend this test if you have a family history of heart disease, stroke, or blood vessel problems. It may also be used to monitor conditions like kidney disease or certain genetic disorders that affect how your body processes homocysteine.

What to Expect Before the Test

No special preparation is usually needed, but you may be asked to fast for 8–12 hours before the test if it involves drawing blood from a vein. If you’re taking medications that affect homocysteine levels (like folic acid or vitamin B12 supplements), let your provider know.

How the Test Is Performed

A healthcare professional will draw blood from a vein in your arm using a small needle. You may feel a slight prick, but it usually doesn’t cause pain. The blood is then sent to a lab for analysis.

What the Results Mean

Results are typically reported as a mass concentration (e.g., micromoles per liter). While reference ranges vary by lab, high levels (above typical thresholds) may signal potential risks that your doctor will discuss with you.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

Homocysteine Level

Frequently asked questions

What Does a High Homocysteine Level Indicate?
Elevated homocysteine levels can increase the risk of blood clots, heart disease, or nerve damage. Your doctor may recommend lifestyle changes (like diet and exercise) or supplements (such as folate, vitamin B6, or B12) to help lower it.
What Does a Low Homocysteine Level Indicate?
Low levels are less commonly associated with health risks, but they may suggest certain genetic factors or deficiencies in vitamins that support homocysteine metabolism.
How Often Should I Get This Test?
Your doctor will determine the best timing based on your medical history, symptoms, or treatment plan. Regular monitoring may be needed if you have conditions like kidney disease or a history of vascular 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