The determination of erythrocyte folate concentration using a two-phase ligand-binding radioassay.

The Determination of Erythrocyte Folate Concentration Using a Two - Phase Ligand - binding

The concentration of folate in erythrocytes was determined using a two-phase ligandbIndIng radloasuy procedure described previously for measuring serum folate. The mean (± SD) folate concentration In erythrocytes of 20 normal subjects was 210 * 67 ng/mI. In 12 patients clinically folate deficient who had normal serum B2 concentration, the mean (± SD) erythrocyte folate was 71 * 39 ng/ml. Incuba...

Inadequate sample-preparation technique as a source of error in determination of erythrocyte folate by competitive binding radioassay.

Radiochemical method for measuring plasma clearance and urinary excretion of pteroylglutamic acid.

A radiochemical procedure is described for specific determination of pteroylglutamate in serum and urine. This method depends on denaturation of methyltetrahydrofolate with peroxide and measurement of the residual folate by a ligand-binding radioassay. The binding determinant for the radioassay is a folate-binding protein, partially purified from chronic myelogenous lekemia cells, that has low ...

Analytical evaluation of a folate radioassay: application to serum and erythrocyte measurements.

Many commercial folate radioassay kits have proven to be unsatisfactory in the past. It has been found that the Schwarz/Mann Iodine-125 folate radioassay kit permits a rapid measurement of folic acid requiring only a single incubation at pH 9.3. At this pH, the relative affinity of pteroylglutamic acid (FA) and N-5-methyltetrahydrofolic acid (MTFA) for the milk binder is the same. Additionally,...

Two radioassays for serum vitamin B12 and folate determination compared in a reference interval study.

For 154 subjects, we verified that vitamin B12 and folate status was normal, using as criteria the average polymorphonuclear lobe count, mean corpuscular volume, and hemoglobin concentration. We then used blood from these subjects to compare values obtained with two radioassay kits, each designed for simultaneous vitamin B12 and folate determination. Although regression analysis showed reasonab...