A patient seated in the chair before a blood draw
In person

Homocysteine

An amino acid tied to B vitamins and heart risk, from one draw.

Loading price
  • 2,000+ lab locations. Find one near you
  • Nothing due at the lab. FSA / HSA accepted
  • Ordered by a licensed clinician

At a glance

Collection
Blood draw
A standard blood draw at the lab.
Preparation
None
Nothing to do ahead of time. Water is fine.
Results
2 to 4 days
Typical turnaround after your visit.
Where
2,000+ lab locations
Nationwide, with nothing due at the lab.

About this test

Homocysteine is an amino acid your body makes as it processes protein. Vitamin B12 and folate help break it down, so levels can run high when those vitamins are low. A high level is considered an independent risk factor for heart and blood vessel disease. No fasting is needed.

For adults 18 and older. Test availability varies by lab location.

Who should take this test?

This test is for adults who want more detail than a standard cholesterol check, or whose healthcare provider is looking at B12 and folate, often with a family heart history.

Ask about this test

Not sure this is the right test?

AI-generated. For information only, not medical advice. Call 911 for an emergency.

What does this test measure?

Your result shows how much homocysteine is in your blood, which can help a healthcare provider look at B vitamin status and add context to heart and blood vessel risk.

Homocysteine
Homocysteine is an amino acid your body makes while processing protein. Vitamins B12, B6, and folate help break it down. A higher level has been associated with heart risk and can also relate to low B12 or folate, kidney function, and some medicines, so it is read in context.
Why it’s measured: Linked to heart risk, and it can also reflect your B12 and folate status.

How it works

  1. Step 1

    Order online

    Check out here. A licensed clinician in your state reviews your order and sends it to the lab.

  2. Step 2

    Visit a lab

    Bring a photo ID to any of 2,000+ lab locations. No fasting needed, and nothing is due at the lab.

  3. Step 3

    Get your results

    Results post to your account, usually in 2 to 4 days, each number next to the lab’s reference range.

Find a lab near you

Choose from 2,000+ lab locations nationwide. Your order works at any of them.

What your results tell you

Homocysteine is reported in micromoles per liter (µmol/L) and compared with the lab’s reference range, which is shown on your report.

  • Your number next to the lab’s reference range
  • Explained in plain language
  • A licensed clinician reviews your order and, if appropriate, orders the test.
  • A lab report you can download and share

A high result has several possible causes, including low B12 or folate, so talk with a healthcare provider about what it means for you.

Clinical-grade testing, from the comfort of home.

From the lab to your report, every step of our process meets the gold standard in medical testing.

  • CLIA-certified labs

    Every lab we partner with is certified under the Clinical Laboratory Improvement Amendments, meeting both state and federal standards with regular independent inspections.

  • We protect your health data

    We protect your health data with encryption and do not sell it. Some results must be reported to public health authorities by law. See our Privacy Notice.

  • Rigorous quality assurance

    All partner labs run regular internal quality checks, participate in proficiency testing, and comply with federal and state lab regulations.

  • Clinician-reviewed reports

    Results are reviewed by an independent, licensed clinician.

Questions

Common questions.

Anything else, our care team answers by phone, text, or email.

Your body uses vitamin B12 and folate to convert homocysteine into other substances. When either is low, homocysteine can build up. Read with another marker called methylmalonic acid, homocysteine can help a healthcare provider look at B12 and folate status.

A raised homocysteine level is considered an independent risk factor for cardiovascular disease, meaning it is linked with risk on its own, apart from cholesterol. A link is not the same as a cause, and a healthcare provider reads it with your other heart risk factors.

People often check it when they want detail beyond a standard cholesterol set, when early heart disease runs in the family, or when a healthcare provider is looking into B12 or folate. It is also part of the Advanced Heart Panel.

Homocysteine does not diagnose a vitamin deficiency or heart disease by itself. For B12 and folate questions it is often read with methylmalonic acid, and a healthcare provider decides whether other tests, such as B12 or folate, would help.

Lab tests are informational and don’t diagnose conditions on their own. Available to adults 18 and older; test availability varies by lab location. A licensed clinician reviews your order and, if appropriate, orders the test. All testing is performed at CLIA-certified laboratories. Not for emergencies: if you think you may be having a medical emergency, call 911.