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Homocysteine, Plasma (Concentration)

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

This test measures the level of homocysteine, an amino acid that can build up in your blood. High levels may increase your risk of certain health issues.

Quick summary

["Homocysteine levels can signal potential heart or blood vessel problems."]

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

Key facts at a glance

LOINC
95699-5
Short code
HJV IgA Spec Ql IA
Synonyms
HJV IgA Spec Ql IA
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
ia
CPT
82784
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 blood vessel issues. It may also be checked if you have symptoms like fatigue, numbness, or weakness. Some genetic conditions or medications can also raise homocysteine levels, prompting this test.

What Does a High or Low Level Mean?

High homocysteine levels may suggest an increased risk of blood clots or damage to blood vessels, which can affect the heart or brain. Low levels are generally not a concern unless caused by specific medical conditions.

How Is This Test Performed?

A blood sample is taken from a vein in your arm. The blood is then sent to a lab where it is analyzed to measure homocysteine concentration using a specialized immunoassay method.

What Are Common Causes?

Factors that may influence homocysteine levels include diet (low in folate, vitamin B6, or B12), certain medications (like some antidepressants or diuretics), kidney disease, and genetic conditions.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Plasma Homocysteine

Frequently asked questions

How long does it take to get results?
Results are typically available within 1 to 3 business days, depending on lab processing times.
What should I do if my homocysteine level is high?
If your results are high, your healthcare provider may recommend dietary changes (e.g., increasing folate, vitamin B6, and B12 intake), supplements, or lifestyle adjustments like quitting smoking or managing other health conditions.
Can I eat or drink anything before the test?
You may eat and drink normally before the test unless instructed otherwise by your provider. Avoiding alcohol for 24 hours before testing may help 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