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Serum/plasma mass 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 and may be linked to certain health risks.

Quick summary

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

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

Key facts at a glance

LOINC
40305-5
Short code
GH 2h p Arg SerPl-mCnc
Synonyms
GH 2h p Arg 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

Why This Test Might Be Ordered

Your healthcare provider may recommend this test if you have a history of heart disease, stroke, or blood vessel problems. It could also be used to monitor conditions like kidney disease, vitamin deficiencies (such as folate or B12), or if you’re taking medications that 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 metabolic panel. Avoid smoking or strenuous activity for a few hours beforehand. Bring any medications you’re taking to your appointment.

What Happens During the Test

A healthcare professional will draw blood from a vein in your arm. You may feel a slight pinch, but it usually doesn’t cause discomfort. The blood sample is then sent to a lab for analysis.

What the Results Mean

Results are compared to general reference ranges, but your specific range may vary based on lab methods and clinical context. High levels may signal an increased risk for vascular issues, while low levels might indicate a deficiency in certain vitamins.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Elevated homocysteine levels are often associated with an increased risk of cardiovascular diseases, such as heart attacks or strokes. It can also be linked to nerve damage (neuropathy) or bone loss (osteoporosis). However, homocysteine alone isn’t diagnostic—it’s usually part of a broader evaluation for underlying conditions like kidney disease, diabetes, or genetic factors.

Short name

Total Homocysteine (Serum/Plasma)

Frequently asked questions

What causes homocysteine levels to be high?
Several factors can raise homocysteine levels, including poor diet (low in folate, vitamin B6, or B12), kidney disease, smoking, alcohol use, or certain medications (like some chemotherapy drugs or diuretics). Genetic conditions, such as mutations in the MTHFR gene, can also play a role.
Can I lower my homocysteine levels naturally?
Yes! Making dietary changes—such as eating more leafy greens, fruits, nuts, and whole grains—can help. Taking folate, vitamin B6, and B12 supplements (under medical supervision) may also support lower levels. Lifestyle changes like quitting smoking, reducing alcohol, and managing stress can also help.
How often should I get this test?
Your provider will determine the frequency based on your health status. If you have a history of high homocysteine or related conditions, they may recommend monitoring every 1–2 years. Regular check-ups with your doctor are the best way to know when to repeat this test.
  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