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Homocysteine (Serum or Plasma)

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 be linked to certain health risks.

Quick summary

["Homocysteine levels can signal potential heart, blood vessel, or nerve issues."]

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

Key facts at a glance

LOINC
79612-8
Short code
L-homoarginine SerPl-sCnc
Synonyms
L-homoarginine SerPl-sCnc
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
1.5
Ref high
9
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
83002
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, stroke, blood clots, or nerve problems. It may also be checked if you have symptoms like fatigue, numbness, or weakness, or if you’re taking certain medications that can affect homocysteine levels.

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’s part of a broader metabolic evaluation. Bring any medications you’re taking to your appointment.

How the Test Works

A small sample of your blood (serum or plasma) is drawn from a vein in your arm. The sample is then analyzed in a lab to measure homocysteine concentration using an immunoassay method.

What the Results Mean

Results are typically reported as a concentration value (e.g., micromoles per liter). High levels may need further evaluation, while normal levels usually indicate no immediate concern.

Reference range

Follicular: 1.5-9.0 mIU/mLN/A

Specimen: serum

For females: inform if menstrual cycle status. For certain tests, timing within menstrual cycle may matter.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Elevated homocysteine levels are associated with an increased risk of cardiovascular disease, including heart attacks and strokes. It may also raise concerns for vascular damage or nerve disorders. Your provider will interpret results in the context of your overall health and symptoms.

Short name

Homocysteine

Frequently asked questions

What causes homocysteine levels to rise?
Several factors can increase homocysteine, including genetics, certain medical conditions (like kidney disease or vitamin deficiencies), smoking, alcohol use, or medications like birth control pills or certain antidepressants.
How long does it take to get results?
Test results are usually available within 1–3 business days, depending on your lab’s processing time.
Can I lower my homocysteine levels naturally?
Yes! Lifestyle changes like improving diet (more folate, vitamin B6, and vitamin B12), staying hydrated, quitting smoking, and managing stress may help. Always discuss changes with your provider before making major adjustments.
  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