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Homocysteine, Serum Concentration

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

This test measures the level of homocysteine, an amino acid in your blood that may be linked to certain health conditions.

Quick summary

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

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

Key facts at a glance

LOINC
55877-5
Short code
Hcys Fld-sCnc
Synonyms
Hcys Fld-sCnc
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 history of heart disease, blood clots, or other vascular conditions. It may also be used to monitor treatment for conditions like vitamin deficiencies (such as folate or B12) or genetic disorders.

What to Expect Before the Test

No special preparation is typically needed, but you may be asked to fast for 8–12 hours before the test if instructed. Bring any medications you’re currently taking, as some may affect results.

How the Test Works

A small sample of your blood is drawn from a vein, usually in your arm. The sample is sent to a lab where it is analyzed to measure homocysteine concentration using an immunoassay method.

What the Results Mean

Results are reported as a concentration value (e.g., micromoles per liter). Higher-than-normal levels may signal increased risk for cardiovascular issues, while lower levels may indicate deficiencies in certain vitamins.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Homocysteine

Frequently asked questions

What does elevated homocysteine mean?
Elevated homocysteine levels may increase the risk of blood clots, heart disease, or stroke. It can also be linked to nerve damage (neuropathy) or kidney problems. Your provider may recommend lifestyle changes, vitamin supplements, or further testing if results are high.
Can diet affect homocysteine levels?
Yes, diet plays a role. Foods rich in folate, vitamin B6, and vitamin B12 (like leafy greens, nuts, and fortified cereals) can help lower homocysteine levels. Avoiding excessive alcohol and maintaining a balanced diet may also support healthy levels.
Is this test always done with other blood tests?
Sometimes yes. Your provider may order it alongside tests for vitamin deficiencies (like B12 or folate) or other markers of cardiovascular risk to get a fuller picture of your health.
  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