HOMOCYSTEINE - RELATIONSHIP TO SERUM COBALAMIN, SERUM FOLATE, ERYTHROCYTE FOLATE, AND LOBATION OF NEUTROPHILS

Serum levels of total homocysteine were studied in the following: 26 h ealthy adults; 79 hospitalised patients in whom serum cobalamin, serum folate, and erythrocyte folate were greater than 230 pmol/L, 12 nmol/ L, and 600 nmol/L, respectively; 32 hospitalised patients whose serum cobalamin was less than 147 pmol/L, compared to 25 patients whose seru m cobalamin was greater than 147 pmol/L but unmatched in any other par ameter; and 194 patients in whom samples were sent for determination o f cobalamin and folate from a neurological service. None of this last group had megaloblastic anaemia. There was a relationship between the elevated concentrations of total homocysteine in serum and low concent rations of serum cobalamin and of erythrocyte folate. This relationshi p was most evident in samples with serum cobalamin <86 pmol/L and eryt hrocyte folate <335 nmol/L, although elevated homocysteine levels were found in some samples where serum cobalamin and erythrocyte folate le vels were greater than these. Serum folate correlated poorly with seru m total homocysteine. There was only a poor-to-fair correlation of neu trophil lobe counts to total serum homocysteine.