Automated haematology analysis to diagnose malaria

Abstract

For more than a decade, flow cytometry-based automated haematology analysers have been studied for malaria diagnosis. Although current haematology analysers are not specifically designed to detect malaria-related abnormalities, most studies have found sensitivities that comply with WHO malaria-diagnostic guidelines, i.e. ≥ 95% in samples with > 100 parasites/μl. Establishing a correct and early malaria diagnosis is a prerequisite for an adequate treatment and to minimizing adverse outcomes. Expert light microscopy remains the 'gold standard' for malaria diagnosis in most clinical settings. However, it requires an explicit request from clinicians and has variable accuracy. Malaria diagnosis with flow cytometry-based haematology analysers could become an important adjuvant diagnostic tool in the routine laboratory work-up of febrile patients in or returning from malaria-endemic regions. Haematology analysers so far studied for malaria diagnosis are the Cell-Dyn®, Coulter® GEN·S and LH 750, and the Sysmex XE-2100® analysers. For Cell-Dyn analysers, abnormal depolarization events mainly in the lobularity/granularity and other scatter-plots, and various reticulocyte abnormalities have shown overall sensitivities and specificities of 49% to 97% and 61% to 100%, respectively. For the Coulter analysers, a 'malaria factor' using the monocyte and lymphocyte size standard deviations obtained by impedance detection has shown overall sensitivities and specificities of 82% to 98% and 72% to 94%, respectively. For the XE-2100, abnormal patterns in the DIFF, WBC/BASO, and RET-EXT scatter-plots, and pseudoeosinophilia and other abnormal haematological variables have been described, and multivariate diagnostic models have been designed with overall sensitivities and specificities of 86% to 97% and 81% to 98%, respectively. The accuracy for malaria diagnosis may vary according to species, parasite load, immunity and clinical context where the method is applied. Future developments in new haematology analysers such as considerably simplified, robust and inexpensive devices for malaria detection fitted with an automatically generated alert could improve the detection capacity of these instruments and potentially expand their clinical utility in malaria diagnosis.

Laboratory Diagnosis of Malaria: Comparison of Manual and Automated Diagnostic Tests

“…This can be attributed to the presence of extracellular pigment and RBC lysis which are reflected in that area [28]. Pseudoeosinophilia by machine compared with manual differential count was observed in 6.25% cases which is comparatively lower than previous report of 39% of cases of pseudoeosinophilia [16, 29]. …”

What is the best strategy for the prevention of transfusion-transmitted malaria in sub-Saharan African countries where malaria is endemic?

“…According to the review from Campuzano-Zaluaga et al , the accuracy for malaria diagnosis using automated haematology analysis may vary according to species, parasite load, immunity and clinical context where the method is applied [51]. Its overall sensitivity ranges from 48.6% to 100%, and its specificity, from 25.3% to 100%.…”

Hematology analyzers to identify malaria and dengue

“…[1] This is the first report on using automated hematology analyzer for help diagnose and differentiate malaria and dengue from other infections. [2][3][4] The common parameters that seem to be specific for malaria include lymphocyte and platelet parameters. The feasibility of using hematology analyzer is very interesting.…”

“…[1] In fact, the use of automated hematology analyzer for determination of malaria and dengue has been in trials for a long time. [2][3][4] The fair diagnostic properties (sensitivity and specificity) of the automated hematology diagnosis can be observed. If this approach is effective, it might help diagnose the diseases for the practitioners who have no experience with two tropical infections.…”

“…The feasibility of using hematology analyzer is very interesting. [2][3][4] Mohapatra et al proposed that the use of hematology analyzer resulted in "a rapid, high throughput device which needs less expertization for the diagnosis of malaria." Focusing on malaria, there are previous reports on using Cell-Dyn ® , Coulter ® GEN·S as well as LH750 automated hematology analyzers.…”