What it measures
Homocysteine is an amino acid made when the body breaks down methionine, which comes from protein in food. Folate, vitamin B12 and vitamin B6 are needed to process it further, so levels tend to rise when any of them is low. The test measures how much is in the blood.
Why people test it
- Measured when vitamin B12 or folate deficiency is being looked into.
- Checked in some people with unexplained blood clots or heart disease at a young age.
- Included in some private heart and nutrition panels.
Typical range
Ranges vary by lab and method, and levels rise with age, are higher in men and are affected by kidney function. Your report shows the lab's own range.
Finger-prick or vein?
A vein sample is usually advised. Red blood cells keep releasing homocysteine after the sample is taken, so labs need it spun or chilled soon after collection.
Some labs ask for a fasting sample, as a protein-rich meal can raise the level for a few hours.