Box plot (median, interquartile range) of DBS-Tg vs median UIC stratified by country. Countries were ranked from lowest median UIC (Morocco, 31.5 µg/L) to highest median UIC (Tanzania, 429.3 µg/L). The top dotted line represents the 97.5 percentile upper reference limit. The middle, solid line represents the median (50th percentile). The bottom dotted line represents the 2.5 percentile lower reference limit.