Tidsskrift for den Norske lægeforening : tidsskrift for praktisk medicin, ny række
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Tidsskr. Nor. Laegeforen. · Sep 1996
[Homocysteine and methylmalonic acid. New tests--for what benefit?].
A serum cobalamin level lower than 250 pmol/l combined with high values of plasma homocysteine and serum methylmalonic acid confirms the diagnosis of vitamin B12 deficiency. A low serum and erythrocyte folate level and high plasma homocysteine confirm folate deficiency. ⋯ In patients with neurologic or psychiatric disorders combined with elevated levels of homocysteine and methylmalonic acid, cobalamin deficiency is likely if these levels decrease during vitamin B12 therapy. The causes of elevated homocysteine levels are often obscure, and homocysteine should therefore not be used as a screening test.