Erythrocytic Interferences in Malaria Diagnosis Using Flow Cytometry on the XN-31: A Pediatric Setting Study in Ouagadougou, Burkina Faso

Abstract

Introduction : The XN‑31 analyzer detects Plasmodium‑infected red blood cells (MI‑RBC) using fluorescence flow cytometry and provides parasitemia results in less than two minutes. However, certain blood samples yield indeterminate results (“abnormal MI‑RBC scattergram”), attributed to erythrocytic interferences.

Objective : To describe the erythrocyte abnormalities associated with indeterminate malaria diagnostic results on the XN‑31 analyzer.

Methods : A prospective cross‑sectional study including cases with indeterminate malaria results on the XN‑31. For each sample, a complete blood count with peripheral smear and reticulocyte count, a thick blood smear, and hemoglobin screening for A, S, and C were performed.

Results : A total of 290 pediatric samples were included, with a median age of 8.5 months, of which 40.3% were neonates and 53.1% male. The thick blood smear was negative for all samples. At least one erythrocyte abnormality was noted in 78.3% of samples, including anemia in 60%, erythroblastosis in 33.4%, reticulocytosis in 29.3%, and abnormal reticulocyte scattergram in 60.3%. Additionally, schistocytes (47.2%), sickle cells (13.8%), target cells (37.6%), and hemoglobinopathies (36.9%) were observed.

Conclusion : In this pediatric cohort, indeterminate results on the XN‑31 were associated with erythroid regeneration and hemolytic signatures, plausible mechanisms of excessive intra‑erythrocytic fluorescence disrupting MI‑RBC clustering by the analyzer. These findings highlight the importance of context‑aware interpretation of XN‑31 results in pediatrics, particularly in endemic areas with a high prevalence of hemoglobinopathies.