3.2 Safety end points The main concern with PQ lies in the risk of severe hemolytic reactions, and a fall in haemoglobin. However, decreasing hemoglobin can also occur following P. vivax malaria. It is therefore vital to monitor for evidence of hemolysis and clinical significant fall in Hb. Hemoglobin concentration was assessed on days 0, 1, 2, 3, 7, 14, 21, 28, and 180, with the lowest levels expected from day 3 to 14.