[Biochemical and hematological measures for determination of folate status in humans. 2. Comparative determination of folate in blood and in erythrocytes].

Criteria to judge the folate supply have been evaluated in previous studies. The present study is examining parameters to estimate the degree of folate deficiency. Serum folate levels and erythrocyte folate concentrations were measured in 116 volunteers (patients). The erythrocyte folate is to a large extend independent of exterior supply and is lowered only in severe chronic deficiency. Low levels of erythrocyte folate indicate longstanding undersupply. Our experiments show that folate concentration of greater than 250 ng per ml erythrocytes indicate adequate supply. Concentrations below this limit are characteristic for chronic folate deficiency. To confirm this statement further studies will take into account the urine concentration of formiminoglutamic acid.