Hematology analyzers to identify malaria and dengue

Dear Sir,

The use of hematology analyzers to identify malaria and dengue” is very interesting. ^[1] The study by Sharma et al. recently proposed that “leukocyte abnormalities quantitated by automated analyzers successfully identified malaria and dengue and distinguished them from other fevers.” ^[1] This is the first report on using automated hematology analyzer for help diagnose and differentiate malaria and dengue from other infections. ^[1] In fact, the use of automated hematology analyzer for determination of malaria and dengue has been in trials for a long time. The feasibility of using hematology analyzer is very interesting. If this approach is effective, it might help diagnose the diseases for the practitioners who have no experience with two tropical infections. Focusing on malaria, there are previous reports on using Cell-Dyn^® , Coulter^® GEN·S as well as LH750 automated hematology analyzers. ^[2],[3],[4] The common parameters that seem to be specific for malaria include lymphocyte and platelet parameters. ^[2],[3],[4] The fair diagnostic properties (sensitivity and specificity) of the automated hematology diagnosis can be observed. ^[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.” ^[3] Focusing on dengue, automated hematology analyzer can be applied in diagnosis. ^[5],[6] Potts et al. mentioned that some parameters platelet, white blood cell and neutrophil counts could be used with clinical features of the patients for discriminating between dengue and other febrile illnesses. ^[5] Furthermore, the use of derived parameters from automated hematology analyzer accompanied with basic clinical data for prediction of severe form of dengue infection (dengue shock syndrome) is also tested. ^[6] In the quoted report, Sharma et al. tried to develop statistical function from parameters derived from LH750 hematology analyzer. ^[1] The recent report by Sharma et al. can give additional data to previous reports since both dengue and malaria were studied. ^[1] In fact, dengue and malaria are both tropical infections and share common endemic areas. Hence, the effective tools for diagnosis of both diseases and discrimination both from other acute febrile illness can be useful. There are many points for consideration. First, based on the study by Sharma et al., it should not possible to tell that LH750 can distinguish malaria and dengue from other tropical infections since there is study on samples derived from any other defined infections (samples from patients with acute febrile illness are not specific). ^[1] Many important tropical infections can give very similar automated hematology analyzer parameter profiles and should be evaluated. The good examples are Chikungunya virus infection and leptospirosis. ^[7],[8] Second, the studied malaria and dengue patients might not homogeneous. There are many kinds of malaria (falciparum, vivax, ovalae and malariae) and there are also many groups of dengue (dengue fever, dengue hemorrhagic fever and dengue shock syndrome). Campuzano-Zuluaga et al. performed an appraisal on automated analyzer in diagnosis of malaria and concluded that “the accuracy for malaria diagnosis may vary according to species, parasite load, immunity and clinical context where the method is applied.” ^[2] Nevertheless, it should remind that the concurrent infections of both diseases, malaria and dengue, is possible and this can be the problem in using hematologic analyzer. ^[9],[10] In fact, the misdiagnosis in cases of concurrent infection is possible despite the use of standard diagnostic approach. ^[9],[10] Third, Sharma et al. mentioned that the automated analyzer technique is good for cost-constrained settings. ^[1] In fact, the diagnosis by classical methods such as blood film examination and tourniquet test for dengue might be significantly cheaper and more cost effective.

Source of Support: None, Conflict of Interest: None

DOI: 10.4103/1755-6783.140263