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Homocysteine, Plasma or Serum, Quantitative

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

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

Quick summary

["Homocysteine levels may help assess your risk for heart disease or blood vessel problems."]

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

Key facts at a glance

LOINC
38486-7
Short code
(Hcys)2 DBS Ql
Synonyms
(Hcys)2 DBS Ql
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 Is This Test Done?

Your healthcare provider may order this test if you have a history of heart disease, stroke, or blood vessel issues, or if you have symptoms like fatigue, numbness, or memory problems. It may also be checked in people with kidney disease or those taking certain medications that affect homocysteine levels.

What Does the Test Measure?

Homocysteine is a compound formed during normal metabolism. High levels may indicate an increased risk of blood clots, heart disease, or nerve damage. The test helps monitor whether your body is breaking down homocysteine properly.

What to Expect Before the Test

No special preparation is usually needed. You may be asked to fast for 8–12 hours before the test if it involves drawing blood from a vein.

What to Expect During the Test

A healthcare professional will insert a small needle into a vein in your arm to draw blood. You may feel a brief pinch, but it usually doesn’t cause discomfort afterward.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Elevated homocysteine levels can increase the risk of cardiovascular disease, including heart attacks and strokes, by promoting blood clot formation. It may also affect nerve function and contribute to conditions like peripheral neuropathy. Lowering homocysteine through diet, supplements (like folate, vitamin B6, and B12), or lifestyle changes may help reduce these risks.

Short name

Homocysteine

Frequently asked questions

What causes high homocysteine levels?
High homocysteine levels can result from genetic factors, certain medical conditions (like kidney disease), or deficiencies in vitamins B6, B9 (folate), and B12. Lifestyle factors, such as smoking or poor diet, may also play a role.
What are the common symptoms of high homocysteine?
Many people with high homocysteine levels have no symptoms at first. However, long-term elevated levels may contribute to fatigue, numbness, tingling in hands/feet, memory issues, or an increased risk of heart disease.
Can homocysteine levels be lowered naturally?
Yes, diet and lifestyle changes can help. Eating foods rich in folate (leafy greens), vitamin B6 (nuts, seeds), and vitamin B12 (meat, eggs, fortified foods) may support lower homocysteine levels. Exercise, avoiding smoking, and managing conditions like diabetes also play a role.
  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