LOGO Erythrocyte tocopherol isomers in the investigation of vitamin E deficiency

We have established a method for erythrocyte α- and γ-tocopherol using reverse-phase HPLC, as an adjunct to plasma measurement in diagnostically difficult situations. The extraction procedure for erythrocytes is more challenging than for plasma, since it requires the complete disruption of red cell membranes prior to extraction into heptane. The derived reference interval for erythrocyte α-tocopherol was 1.3-5.7 μmol/l and for plasma 25- 60 μmol/l. According to our results for vitamin E-replete subjects, the mean ratio of erythrocyte to plasma α-tocopherol concentration is 0.10 (range 0.03-0.19). This figure is somewhat lower than previous reports, which have suggested mean WHY MEASURE RED CELL TOCOPHEROLS? Serum and tocopherol concentrations are commonly used as markers of vitamin E status, but in certain conditions may have a limited diagnostic value. For example, the serum level in patients suffering from ataxia with vitamin E deficiency (AVED syndrome) can fluctuate rapidly during supplementation, rather than achieving a steady state. The erythrocyte tocopherol content is less susceptible to fluctuations after supplementation and is a possible marker of tissue vitamin E status. The maintenance of serum concentrations of -tocopherol normally depends on the action of