Advanced cardiovascular
Homocysteine
Methionine metabolite; high values reflect B-vitamin deficiency and modest CV risk.
Sample
Serum or EDTA plasma, fasting
Clinical reference range
5 to 15 µmol/L
Adult
Conv: 5–15 µmol/LFunc: 5–8 µmol/L
Biology
What it measures
Remethylated to methionine using B12/folate, or transsulfurated using B6.
Clinical use
Why we order it
Screen for B12/folate deficiency, MTHFR variants, and hyperhomocysteinuria.
Differential
Causes of abnormal values
Causes of HIGH
- ↑B12, folate, B6 deficiency
- ↑MTHFR C677T homozygous
- ↑Renal failure
- ↑Hypothyroidism
- ↑Methotrexate
Pitfalls
Pre-analytic & interpretation traps
- !Lowering homocysteine with B vitamins does not reduce CV events (HOPE-2, VISP).
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