Key Information

Appropriate Tests

Acquired, especially

Associations with increased risk of atherothrombotic and venous thromboembolic diseases are recognised.


  • Folate deficiency (common)
  • Vitamins B12 and B6 deficiency
  • Smoking
  • Renal insufficiency
  • Hypothyroidism
  • Drug-induced (anticonvulsants, Methotrexate, Steroids, Cyclosporine)

Serum Vitamin B12 and red cell Folate. Urea and Electrolytes and thyroid function (Thyroid stimulating hormone).

Inherited, including methyltetrahydrofolate reductase thermolabile variant (MTHRF C677T mutation);

  • Homozygous individuals with the MTHFR C677T mutation have increased homocysteine levels In the presence of low folate stores
  • Associations between MTHFR C677T and coronary artery disease have recently been questioned

Homocystinuria (deficiency of cystathione beta-synthase).

  • The homozygous state is characterised by marfanoid habitus, lens dislocation and atherothrombotic events.
  • In comparison, the heterozygous state is characterised by normal homocysteine levels and a similar vascular risk when compared to the general population.



Undas et al. Thromb Haemost 2005; 1994: 907-915.

Lewis et al. BMJ 2005; 331: 1053-1056.

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