Malaria Diagnosis Using Automated Analysers: A Boon for Hematopathologists in Endemic Areas
Aminder Singh · JOURNAL OF CLINICAL AND DIAGNOSTIC RESEARCH · 2015
IntrOductIOnHaematological abnormalities are common in acute febrile tropical illnesses.Malaria is a major health problem in tropics.In endemic areas especially in the post monsoon season, it is not practical to manually screen all peripheral blood films (PBF) for malarial parasite.The automation in haematology helps in analysing various parameters which can help the pathologist for a more diligent search for malarial parasites in peripheral blood smear thus allow immediate start of specific therapy to the patient [1].Automated analysers offer rapid, sensitive and cost effective screening of all samples.VCS technology of automated analysers detect changes in volume, conductivity and scatter properties of monocytes & lymphocytes which have been activated by malarial parasites & reflected as the heterogeneity of the volume in scatter grams along with infected RBC's depicted in the non WBC's areas of the scatter gram called ghost areas.Abnormal WBC histogram peaks at the threshold generating a "suspect malaria" flags are also evident.A flag to indicate the potential presence of malaria parasites could be a valuable diagnostic method for the detection of malaria and may become a routine parameter in the diagnosis [2].Hence it was thought pertinent to analyze the coulter data with the peripheral smears in suspected cases of malaria. MAtErIALs And MEtHOdsA total of 200 patients presented with fever or clinically suspected malaria, in Department of Clinical Pathology, Dayanand Medical College and Hospital Ludhiana during a period of 21 months (from March 2013 to November 2014) were included in the study.Inclusion criteria: EDTA blood samples from both outpatient & admitted febrile patients with or without clinical suspicion of malaria were included in the study. Exclusion criteria:Patients without history of fever, inadequate EDTA blood samples, clotted samples, peripheral blood smear showing normoblastemia.The informed consent was taken from patients by respective treating physicians.Institutional ethical standards have been followed however the ethical clearance was not required as the study includes the examination of blood samples given by patients for their routine check up without disclosing their identities.The blood samples were analysed using Beckman coulter LH-750.The abnormal scatter grams and additional peaks in WBC histograms were observed diligently & compared with normal controls.Haematological abnormalities like anaemia, leucopenia, thrombocytopenia, lymphocytosis, monocytosis, pseudoeosinophilia and reticulocyte count were also evaluated.Peripheral smears were fixed with 95% alcohol, and stained with routine Giemsa stain and were examined by at least two independent pathologists. stAtIstIcAL AnALysIsStatistical analysis was done by using software Epi-Info version 7.1.4freely available from CDC website.Fisher exact test was applied to calculate the p-value and value < 0.05 was considered as significant.Final identification of plasmodium species was done independently by peripheral blood smear examination by two pathologists. rEsuLtsOf all the 200 cases evaluated, majority were males with male female ratio of 3.1:1.The mean age was 33.6 years with youngest being one-year-old female and eldest was 85-year-old male.Majority of the patients had Plasmodium vivax (88%) while Plasmodium falciparum was seen in 12% cases [Table /Fig- 1a-d].Abnormal scatter grams were observed in all the cases of malaria.