The prognostic and diagnostic value of intraleukocytic malaria pigment: an individual patient data pooled meta-analysis of 32,000 patients with severe falciparum malaria in Africa and Asia

Severe falciparum malaria is a major cause of death in tropical countries, particularly in African children. Accurate diagnosis and prognostic assessment are critical to clinical management. In 6,027 prospectively studied patients diagnosed with severe malaria we assessed the prognostic value of peripheral blood film counts of malaria pigment containing polymorphonu-clear leukocytes (PMNs) and monocytes. We combined these results with previously published data and show, in an individual patient data meta-analysis ( n =32,035), that the proportion of pigment containing PMNs is predictive of in-hospital mortality. In African children the proportion of pigment containing PMNs is a strong indicator that the primary diagnosis is severe malaria, and it adds to the prognostic assessment from simple bedside examination, and to the conventional malaria parasite count. Microscopy assessment of pigment containing PMNs is simple and rapid, and should be performed in all patients hospitalised with suspected severe malaria.