Hematological analyzer Sysmex XN-1000: Contribution of the “iRBC?” flag in the diagnostic guidance of malaria in endemic areas

The Sysmex XN-1000 cellular hematology analyzers, widely used in Burkina Faso, can provide information on Plasmodium infection with the "iRBC?" flag triggered during a blood count. This study aims to evaluate the contribution of this alarm to the diagnostic orientation of malaria in an endemic area. The samples were collected between August and September 2023. The blood was sampled on EDTA tubes and the blood count was performed on the Sysmex XN-1000. The Sysmex XN-31 was used as a reference diagnostic method for malaria and identification of the Plasmodium falciparum species. Identification of the non-falciparum species and non-plasmodial inclusions was made on blood smears stained with the RAL MCDh kit. 148 samples were analyzed. Children under 5 years of age represent 63.5%, and females 52.7%. The "iRBC?" flag shows a PPV and an overall specificity to malaria of 100%. Depending on the species, the sensitivity was 12.3% (13/106) for P. falciparum and 83.3% (5/6) for P. malariae. Non-plasmodial inclusions were not associated with triggering this flag. This alarm triggered by the XN series automatons can help to anticipate the diagnosis of malaria. Particular attention from the biologist is necessary during biological validation: the presence of this alarm should lead to specific malaria research, but its absence should not lead to exclude malaria, especially with P. falciparum.