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Serum or plasma concentration of total homocysteine

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

This test measures the amount of homocysteine, an amino acid that can build up in your blood. High levels may be linked to certain health risks.

Quick summary

["Homocysteine levels help assess risk for heart disease and other conditions."]

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

Key facts at a glance

LOINC
36009-9
Short code
MRA Hrt
Synonyms
MRA Hrt
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
mr-angio
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 doctor may recommend this test if you have a history of heart disease, stroke, or kidney problems. It could also be part of routine screening for those at higher risk of vascular issues or genetic conditions like homocystinuria.

What to Expect Before the Test

No special preparation is needed, but you may be asked to fast for 8–12 hours before the draw if your lab uses a fasting protocol. Wear a loose shirt for easy access to your arm.

What Happens During the Test

A healthcare professional will insert a small needle into your arm to draw blood. The process takes about 5 minutes, and you may feel a brief pinch. The blood sample is sent to a lab for analysis.

What the Results Mean

Results are typically reported as a concentration value (e.g., micromoles per liter). High levels may signal increased risk for blood vessel damage or cardiovascular disease, while normal levels suggest no immediate concern.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Total Homocysteine

Frequently asked questions

What questions might you have about this test?
This test is often used alongside other blood tests (like vitamin B12 or folate) to evaluate metabolic health. High homocysteine alone doesn’t diagnose a condition but may prompt further investigation if risks are present.
How long will I need to wait for results?
Results are usually available within 1–3 business days, depending on your lab’s processing time. Your doctor will discuss them with you during your follow-up visit.
Can I lower my homocysteine levels naturally?
Yes! Dietary changes—such as increasing folate-rich foods (leafy greens, beans), vitamin B6 (nuts, whole grains), and vitamin B12 (meat, dairy)—along with quitting smoking and managing blood pressure can help. Always consult your doctor before making major changes.
  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