Skip to content

Homocysteine (Serum or Plasma Mass Concentration)

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

This test measures the level of homocysteine, an amino acid that may be linked to certain health risks when levels are too high.

Quick summary

["High homocysteine levels may signal increased cardiovascular risk."]

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

Key facts at a glance

LOINC
2430-7
Short code
(Hcys)2 SerPl-mCnc
Synonyms
(Hcys)2 SerPl-mCnc
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

What Is Homocysteine?

Homocysteine is a sulfur-containing amino acid produced during normal metabolism. While it plays a role in protein synthesis, high levels can contribute to damage in blood vessels and increase the risk of heart disease or stroke. Your body naturally breaks down homocysteine, but certain factors—like diet, genetics, or health conditions—can keep it elevated.

Why Might You Need This Test?

Your doctor may order this test if you have symptoms of vascular disease, a history of heart problems, or conditions like kidney disease, diabetes, or pernicious anemia. It may also be part of a routine check for individuals at higher risk of cardiovascular issues.

How Is the Test Performed?

A blood sample is drawn from a vein, usually in your arm. The sample is sent to a lab where it’s analyzed to measure homocysteine levels. Results are typically available within a few days.

What Do Results Mean?

Results are compared to reference ranges specific to your lab. While exact values vary, high levels may warrant further investigation into underlying causes, such as vitamin deficiencies or genetic factors.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Homocysteine

Frequently asked questions

What Are Common Causes of High Homocysteine?
High homocysteine levels can result from deficiencies in vitamins B6, B12, or folate, chronic kidney disease, certain medications, or genetic conditions. Lifestyle factors like smoking, obesity, or poor diet may also play a role.
What Are Common Causes of Low Homocysteine?
Low homocysteine levels are less commonly associated with clinical concern unless they’re part of a broader metabolic or genetic disorder. Rarely, they may be linked to certain medications or metabolic syndromes.
How Can I Lower Homocysteine Naturally?
Eating foods rich in folate (leafy greens), vitamin B12 (meat, eggs), and vitamin B6 (whole grains) may help. Staying hydrated, avoiding smoking, and managing chronic conditions like diabetes can also support healthier levels.
  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