Dried blood microsample-assisted determination of vitamins: recent developments and challenges

Abstract Although vitamin deficiencies are a well-known issue, monitoring of the vitamin status and diagnosis of vitamin deficiencies in remote regions is a complicated task. Dried blood microsampling, as an alternative sampling strategy, could offer a solution to the several drawbacks related to conventional venipuncture. Although highly relevant, the number of microsampling procedures that has been developed for assessing vitamins in dried blood samples is rather limited, indicating the challenging nature of the subject. This review discusses several challenges inherent to vitamin analysis in microsamples, thereby covering topics including sampling strategy, hematocrit (Hct) effect, sample preparation, calibration, assay sensitivity, stability, and clinical interpretation of the results.