Comparative Malaria Diagnosis Using LH750 Beckman Coulter Automated Analyser in India: A Cross Sectional Case Control Study

Abstract

Objective: To study the VCS pattern in patients with malaria and compare it with patients having fever who were negative for malarial parasite (P. falciparum, vivax, malariae and ovale) and normal individuals and to determine whether a further adaptation of the discriminant factor is needed using additional parameters from the VCS data analysis using Beckmann Coulter LH 750. Design: Cross sectional Case control study. Setting: Clinical Laboratory and Haematology Department, KMC, India. Patients: Ninety-three Malaria positive samples and fifty malaria negative samples by QBC method comprised the Case and hundred healthy adult samples formed the Control group. Interventions: All blood samples were analysed using LH750 Beckman Coulter for VCS data of the neutrophils, lymphocytes, monocytes and eosinophils and compared between Malaria positive, Malaria negative and Control Group. Main Outcome Measure: Discriminant Factor. Results: The difference in SD volume of the lymphocyte and monocyte among malaria positive and negative were statistically significant. By using logistic regression, the “Malaria factor” is defined. ROC analysis showed using a cut-off value of 2.7 as malaria factor derived from SD volume, specificity of 92.5 and sensitivity of 83.7 with a PPV of 88.6% and NPV of 89.1% were obtained whereas, specificity and sensitivity obtained using SD conductivity (91 and 75.5 respectively) and SD scatter (68.7 and 57.1 respectively) were significantly less. Conclusions: A “suspect malaria” flag could be generated on the analyser, allowing the detection of cases of unsuspected malaria and therefore, early diagnosis of the disease with the potential of reducing the possibility of serious complications however this is not a confirmative test.