Erhardt JG and Rohner F
March 2013, Poster Presentation – International Congress on Hidden Hunger, Stuttgart, Germany
The WHO estimates that vitamin A (VA) deficiency globally affects over 190 million preschool age children. A reliable measurement of the VA status is thus essential to determine the public health relevance of VA deficiency and to assess the impact of interventions aiming to reduce VA deficiency. The currently most common VA assessment method is serum retinol by HPLC, but the measurement of retinol-binding protein (RBP) is gaining importance. It can be measured much more efficiently and easily combined with indicators for the iron and infectious status. Yet, to date, there is still uncertainty whether the absolute values of both measurements are directly comparable, and varying thresholds for defining VA deficiency are proposed. The results of this study indicate that the often observed differences between the absolute values of RBP and retinol are caused by analytical differences and can be minimized by using the same calibrators for both methods. This calls for caution prior to establishing separate thresholds for RBP and retinol, as this may induce confusion within the program managers implementing VA interventions in developing countries.