Homocysteine
Measures homocysteine, a protein-breakdown product B vitamins help clear. Doctors order it when heart risk, stroke history, or B-vitamin deficiency is on the table.
When your body digests protein, it spins off homocysteine as a stepping-stone on the way to other building blocks. Folate and B12 are the cofactors that keep that assembly line moving; when they run short, homocysteine can pile up in the blood. Cardiologists and primary-care teams sometimes add the test when family history, prior stroke, or unclear anemia makes vessel health and B-vitamin status worth a closer look. Genetics can nudge the number too, so the result is read next to B12, folate, and diet, not as a lone fortune teller. A high value opens questions; it does not rewrite your history overnight.
Self-Pay Price Comparison
| Provider | Price | vs. Highest | Order |
|---|---|---|---|
Quest QuestHealth self-pay | $75.00 | Save $4.00 | Order · Quest |
LabCorp Labcorp OnDemand | $79.00 | Highest | Order · LabCorp |
GoodLabs Discount lab network | $13.00Best value | Best price | Order · GoodLabs |
What This Test Measures
This order returns total homocysteine as one concentration. Here is what that line is tracking:
Amino acid intermediate made when protein breaks down; high levels often track with low B12 or folate intake or genetics that slow conversion, very low levels are uncommon and usually reflect supplements or aggressive therapy rather than a problem by themselves.
How to Read Your Results
Homocysteine moves with vitamins, kidney function, and genetics. Here is how to read the three result shapes people see most:
| Marker | Normal Range | If Flagged | What It Might Mean |
|---|---|---|---|
| Homocysteine (elevated) | Labs print their own µmol/L interval; MedlinePlus homocysteine test materials describe high levels as tied to higher heart and stroke risk in population studies, not as a personal timer. | high | High values often send doctors toward B12, folate, diet, meds, and genetics. Kidney function can also raise the number because clearance drops. One draw starts the workup; it rarely ends it. |
| Homocysteine (low or low-normal) | Very low results are uncommon and often follow supplements or therapy that successfully moved the pathway. | low | A low number is usually not an emergency signal on its own. Your doctor still checks whether medicines or vitamins explain the shift. |
| Homocysteine (borderline with normal B12 on the same day) | Serum B12 can look adequate while functional shortage still exists; methylmalonic acid sometimes helps split that knot. | abnormal | Conflicting vitamins and symptoms are exactly when clinicians add second markers or repeat labs after repletion, rather than chasing a single threshold. |
When to Order
Family history of early heart attack or stroke
Homocysteine is one extra data point when standard risk factors look tame but the family story is loud.
Known or suspected B12 or folate shortage
High homocysteine can line up with macrocytic blood counts or neuropathy symptoms; the test helps steer replacement and repeat labs.
Recurrent clotting events under workup
Specialists sometimes bundle homocysteine into broader thrombophilia panels when the timeline fits their protocol.
Vegan diet without structured supplementation
B12 intake can run thin; homocysteine can rise before storage B12 looks dramatic, so the pair is often read together.
Post-bariatric or malabsorption follow-up
Surgery and gut disease both shift B-vitamin absorption; homocysteine can move early when intake changes.
Prep & Logistics
- Fasting
- Typically no fasting
- Sample
- Blood draw (some labs use plasma; follow your report footnotes)
- Results
- Usually 24-48 hours; many portals update the same day or the next.
- Referral
- Often self-order (check local rules)
- Markers
- Total homocysteine concentration (commonly µmol/L). Interpretation depends on the assay and whether the lab used serum or plasma.
Tests That Pair With This One
Storage B12 when homocysteine is high and the diet or absorption story is unclear.
Dietary folate snapshot when homocysteine is up and macrocytic patterns or pregnancy planning overlap.
Functional B12 check when serum B12 looks normal but homocysteine and symptoms disagree.
Cholesterol fractions when the reason for testing is cardiovascular risk stratification.
FAQ
My homocysteine is high—do I just start B vitamins?
Not automatically. B12 and folate deficiency raise it, but so can kidney disease, genetics, and some medicines. Blind megadosing can mask B12 injury while nerves suffer—your clinician usually pairs treatment with the cause.
Will a multivitamin skew the result?
B vitamins in pills can lower homocysteine over days to weeks. Tell your doctor exactly what you take and whether you stopped anything before the draw so the timeline makes sense.
Does high homocysteine mean I have the MTHFR gene variant?
Not automatically. Genetics can contribute, but deficiency, kidney disease, smoking, and some medicines move the number too. Gene tests are a separate order when your team thinks they add value.
Is this the same as a cholesterol test?
No. Homocysteine is an amino acid marker often grouped in heart-risk conversations; lipids are separate particles. Many people run both when the question is overall cardiovascular risk.
Sources
Prices pulled directly from provider websites and verified by hand. Reference context from MedlinePlus where linked. Not generated by AI.
- GoodLabs - product page (pricing context)(verified 2026-03-23)
- Quest - consumer lab shop (pricing context)(verified 2026-03-23)
- LabCorp OnDemand - homocysteine test (pricing context)(verified 2026-03-23)
- MedlinePlus - Homocysteine Test overview
- Clinical context: LabRecon editorial team. Not medical advice. For informational use only.
Elevated homocysteine is associated with increased cardiovascular and thrombotic risk. May indicate B6, B12, or folate deficiency or MTHFR variant.