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Homocysteine, Serum or Plasma Concentration

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

This test measures the level of homocysteine, a type of amino acid found in your blood. It helps assess your risk for certain health conditions.

Quick summary

["Homocysteine levels can indicate risks for heart disease and blood vessel problems."]

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

Key facts at a glance

LOINC
54302-5
Short code
(Hcys)2 DBS-sCnc
Synonyms
(Hcys)2 DBS-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 Is This Test Done?

Your healthcare provider may order this test if you have a history of heart disease, blood clots, or other vascular conditions. It may also be checked if you have symptoms like fatigue, numbness, or weakness that could relate to circulation issues. Sometimes, it’s part of routine screening for people with risk factors like diabetes, kidney disease, or genetic conditions.

What to Expect Before the Test

No special preparation is needed, but you may be asked to fast for 8–12 hours before the test if it’s part of a metabolic panel. Bring any medications you’re taking, as some may affect results. Avoid smoking or consuming alcohol for a few hours before testing.

What Happens During the Test?

A healthcare professional will draw blood from a vein in your arm. The blood sample is sent to a lab for analysis using a sensitive method to measure homocysteine concentration.

What Do Results Mean?

Results are compared to general reference ranges, but individual needs vary. High levels may signal increased risk for cardiovascular issues, while low levels are less commonly associated with concern unless part of a broader evaluation.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Homocysteine

Frequently asked questions

What causes homocysteine levels to be high?
High homocysteine levels can result from genetic factors, certain medications (like some blood thinners or diuretics), vitamin deficiencies (especially folate, vitamin B6, or vitamin B12), kidney disease, or chronic health conditions like diabetes.
Can I lower my homocysteine levels?
Yes! Lifestyle changes such as improving diet (rich in folate, B vitamins, and healthy fats), quitting smoking, and managing conditions like diabetes can help. Your provider may also recommend supplements if deficiencies are identified.
Does this test replace other blood tests?
No. This test is often used alongside other blood work (like cholesterol or lipid panels) to assess cardiovascular risk. Your provider will use the full picture of your health to guide treatment decisions.
  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