Serumalpha- and gama-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 therefore a possible marker of tissue vitamin E status. The maintenance of serum concentrations of alpha-tocopherol normally depends on the action of alpha-tocopherol transfer protein, secreted by hepatocytes, to preferentially take up alpha-tocopherol from the portal blood, while other forms of vitamin E are more rapidly metabolized and excreted. As a result, blood and cellular concentrations of other vitamin E isomers are lower than those of alpha-tocopherol and have been the subjects of less research. The erythrocyte tocopherol content is thus a possible marker of tissue vitamin E status in subjects with gross lipid abnormalities and also in subjects suspected of having AVED syndrome, in which there is an abnormality of alpha-tocopherol transfer protein.

Patient Instructions:

Avoid vitamin E containing supplements for 24-48 hours prior to testing

Clinical Indications:

Erythrocyte tocopherol measurement has a role in the investigation of difficult cases of vitamin E deficiency. There is a good correlation between between serum and erythrocyte gamma-tocopherol, but not between serum and erythrocyte alpha-tocopherol, which reflects the important role of alpha-tocopherol transfer protein in the maintenance of body vitamin E status. There are no previous reports in the scientific literature of the erythrocyte /plasma gamma -tocopherol ratio. Our results for vitamin E-replete subjects suggest a range for the erythrocyte /plasma a-tocopherol ratio of 0.03-0.19 (mean value 0.10), which is lower than that of previous investigators. Our results also suggest a range for the erythrocyte /plasma gamma -tocopherol ratio of 0.11-0.67 (mean value 0.28), which underlines the different physiological mechanisms for the tissue handling of tocopherol isomers.


Sample Requirements:

Green (lithium heparin) and gold (clotted blood sample) capped blood cllection tubes - must reach Biolab within 24 hours of collection

Postal Samples:


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