A, Median normalized histidine-rich protein 2 (HRP2) concentrations over time since initiation of antimalarial treatment at day 0, stratified by treatment outcome in patients from Angola, showing a spike in the HRP2 concentration on the day of treatment failure. B, After exclusion of day of treatment failure data, cases of adequate clinical and parasitological response (ACPR) and reinfection followed a similar linear decline, but cases of recrudescence showed a different clearance behavior.