Lab test glossary · Other
Homocysteine: what it means
Homocysteine is an amino acid tied to B-vitamin status; high levels are associated with cardiovascular risk and often reflect low B12, folate, or B6.
What it measures
Homocysteine is an amino acid your body normally recycles with the help of B vitamins (B12, folate, and B6). When those are low — or with certain genetic or kidney factors — homocysteine builds up. Elevated levels are associated with a higher cardiovascular risk, though whether lowering it changes outcomes is still debated.
Typical range
Often roughly 5–15 µmol/L.
Reference ranges differ between labs and are printed on your own report — always read your result against that range, not a general one.
What a high result can mean
- Low vitamin B12, folate, or B6
- Reduced kidney function
- Genetic factors and some medications
A high value is a starting point for a conversation, not a diagnosis — many causes are benign or temporary.
Why the trend matters
Homocysteine responds to B-vitamin status, so a trend shows whether addressing a deficiency is bringing it down.
When to talk to your doctor
Discuss a high homocysteine with your doctor, who may check your B-vitamin levels as a first step.
This page is general education about a common lab test — it isn’t medical advice and can’t interpret your specific result. What a value means depends on your history, symptoms, and the rest of your labs, which is a conversation for you and your clinician.