Homocysteine Levels Test
This page explains the homocysteine levels test, what it measures, and how to arrange it. A homocysteine levels test measures the amount of homocysteine, an amino acid (a building block of protein), in your blood. It is usually ordered to look for a possible vitamin B12, folate, or B6 deficiency, or as part of checking cardiovascular risk in certain people.
- Sample type
- blood
- Category
- Cardiac
- Turnaround
- 1-3 business days
- Price
- $136
- Referral
- Not required
A homocysteine levels test measures the amount of homocysteine, an amino acid (a building block of protein), in your blood. It is usually ordered to look for a possible vitamin B12, folate, or B6 deficiency, or as part of checking cardiovascular risk in certain people.
What it measures
- Total homocysteine — The main result, reported as a concentration in the blood.
- Vitamin B12 — Often checked alongside homocysteine because low B12 can raise it.
- Folate (folic acid) — A B vitamin that helps the body clear homocysteine.
- Vitamin B6 — Another B vitamin involved in homocysteine breakdown.
- Kidney function markers — Homocysteine can rise when the kidneys are not filtering well.
Who it is for
It is usually ordered by a primary care clinician, cardiologist, or hematologist. It may be used when someone has unexplained B-vitamin deficiency, a family history of early heart disease, or a blood-clotting concern.
Preparation
Fasting is often recommended, but not always required; follow the instructions from your clinician or lab. Tell the lab about any vitamins, supplements, or medications you take, since these can affect the result.
Results and what they mean
Results are reported as a number with a reference range, and levels above the range are called elevated. A clinician interprets the result together with your symptoms, diet, supplements, and other tests; it is not a diagnosis on its own. This is general information, not medical advice.
How to order this test
- Choose the test and place a confidential order online.
- Select a certified collection site and pick a time that suits you.
- Have your specimen collected — most draws take only a few minutes.
- Review results in a secure portal, typically within 1–3 days.
Preparation, hours, and pricing vary by site; confirm details directly with the lab before your visit.
Availability by state
Direct-access online ordering for the homocysteine levels test is available in most states. It is currently unavailable in 6 states:
Everywhere else you can order confidentially and collect your sample at a certified site. Browse by state →
Frequently asked questions
Do I need to fast for this test?
Sometimes. Many labs ask for an 8- to 12-hour fast, but others do not. Check with your clinician or the lab before your appointment.
Can vitamins change my homocysteine level?
Yes. B12, folate, and B6 supplements can lower homocysteine, so tell your clinician what you take and when you last took it.
What does a high result mean?
It can be linked to low B vitamins, kidney problems, some medicines, or inherited factors. Only a clinician can explain what your specific result means.
Is this test used to diagnose heart disease?
No. It is one piece of information that may be considered with other risk factors; it does not diagnose heart disease by itself.