TKT and Thiamine deficiency: This prevalence was higher than the prevalence of 13–30% reported by two studies in Lao PDR in which thiamine deficiency was defined both in terms of a basal erythrocyte transketolase (ETK) activity < 0.59 micromoles/min/gHb and an activation coefficient of ETK α > 31% [14, 19, 20, 65].