Surmised total leucocyte counts miscalculate the parasite index of Plasmodium vivax malaria patients of tertiary and primary care settings in South-Western India

Kumar, Rishikesh and Madivala, Sathish Kitta and Prabhu, Prashantha and Kamath, Asha and Herikudru, Ashok and Vidyasagar, Sudha and Shastry, Ananthakrishna Barkur and Saravu, Kavitha (2015) Surmised total leucocyte counts miscalculate the parasite index of Plasmodium vivax malaria patients of tertiary and primary care settings in South-Western India. Malaria Journal, 14 (163). pp. 1-8.

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Abstract

Background: For the calculation of parasite index (PI) by microscopy method, an assumed total leucocyte count (TLC) of 8,000/μL is used conventionally. However, due to obvious variation in the population and individual TLCs, use of 8,000/μL may result in either over/underestimation of the PI. Methods: This study was aimed at ascertaining the utility of 8,000/μL TLC, as well as other assumed TLCs, with respect to measured TLC for the calculation of PI. A tertiary care hospital and five primary health centres were the base for the prospective study conducted among microscopically proven, symptomatic Plasmodium vivax mono-infection patients aged ≥18 years. PIs calculated by assumed TLCs ranging from 4,000-11,000/μL were compared with those calculated by measured TLCs. Geometric mean with 95% confidence interval, Bland-Altman plot and Wilcoxon signed rank test were used for statistical analysis. Results: A total of 284 P. vivax mono-infection patients, including 156 from a tertiary care hospital and 128 from five primary health centres, were recruited in the study. Assumed TLCs below 5,000 cell/μL and above 5,500 cell/μL in tertiary care setting resulted in significant (p <0.05) underestimation and overestimation, respectively. However, in primary health centres, it was an assumed TLC of 5,000 cell/μL, below and above which there was significant (p <0.05) underestimation and overestimation observed, respectively. Conclusions: Assumed TLC of 8,000/μL is not suitable for the calculation of PI. Either actual TLC of the patient should be measured or a representative TLC should be derived for the population under investigation for any study requiring calculated PI by microscopy.

Item Type: Article
Uncontrolled Keywords: Malaria; plasmodium vivax; parasite index; parasite density; assumed total leucocyte count; total leucocyte count.
Subjects: Medicine > KMC Manipal > Medicine
Depositing User: KMC Library
Date Deposited: 24 Sep 2015 09:34
Last Modified: 24 Sep 2015 09:34
URI: http://eprints.manipal.edu/id/eprint/144065

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