Estimating malaria parasite density: assumed white blood cell count of 10,000/μl of blood is appropriate measure in Central Ghana

<p>Abstract</p> <p>Background</p> <p>White blood cells count (WBCc) is a bedrock in the estimation of malaria parasite density in malaria field trials, interventions and patient management. White blood cells are indirectly and relatively used in microscopy to estimate t...

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Main Authors: Adu-Gyasi Dennis, Adams Mohammed, Amoako Sabastina, Mahama Emmanuel, Nsoh Maxwell, Amenga-Etego Seeba, Baiden Frank, Asante Kwaku, Newton Sam, Owusu-Agyei Seth
Format: Article
Language:English
Published: BMC 2012-07-01
Series:Malaria Journal
Online Access:http://www.malariajournal.com/content/11/1/238
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author Adu-Gyasi Dennis
Adams Mohammed
Amoako Sabastina
Mahama Emmanuel
Nsoh Maxwell
Amenga-Etego Seeba
Baiden Frank
Asante Kwaku
Newton Sam
Owusu-Agyei Seth
author_facet Adu-Gyasi Dennis
Adams Mohammed
Amoako Sabastina
Mahama Emmanuel
Nsoh Maxwell
Amenga-Etego Seeba
Baiden Frank
Asante Kwaku
Newton Sam
Owusu-Agyei Seth
author_sort Adu-Gyasi Dennis
collection DOAJ
description <p>Abstract</p> <p>Background</p> <p>White blood cells count (WBCc) is a bedrock in the estimation of malaria parasite density in malaria field trials, interventions and patient management. White blood cells are indirectly and relatively used in microscopy to estimate the density of malaria parasite infections. Due to frequent lack of facilities in some malaria-endemic countries, in order to quantify WBCc of patients, an assumed WBCc of 8.0 X 10(9)/L has been set by the World Health Organization to help in estimating malaria parasite densities.</p> <p>Methods</p> <p>This comparative analysis study, in Central Ghana, compiled laboratory data of 5,902 <it>Plasmodium falciparum</it> malaria parasite positive samples. Samples were obtained from consented participants of age groups less than five years. Full blood counts (FBC) of participants’ samples were analysed using the ABX Micros 60 Haematology Analyzer. Blood slides were read by two competent microscopists to produce concordant results. All internal and external quality control measures were carried out appropriately. Parasite densities were calculated using participants’ absolute WBCc and assumed WBCc of 5,000 to 10,000 per microlitre of blood.</p> <p>Results</p> <p>From the 5,902 Pf malaria positive samples, the mean (SD) WBCc and geometric mean parasite density were 10.4 (4.6) × 10(9)/L and 7,557/μL (95 % CI 7,144/μL to 7,994/μL) respectively. The difference in the geometric mean parasite densities calculated using absolute WBCs and compared to densities with assumed WBCs counts were significantly lower for 5.0 × 10(9)/L; 3,937/μL, 6.0 × 10(9)/L; 4,725/μL and 8.0 × 10(9)/L; 6,300/μL. However, the difference in geometric mean parasite density, 7,874/μL (95 % CI, 7,445/μL to 8,328/μL), with assumed WBCc of 10.0 × 10(9)/L was not significant.</p> <p>Conclusion</p> <p>Using the assumed WBCc of 8.0 X 10(9)/L or lower to estimate malaria parasite densities in Pf infected children less than five years old could result in significant underestimation of parasite burden. Assumed WBCc of 10.0 × 10(9)/L at 95 % CI of geometric mean of parasite density statistically agreed with the parasite densities produce by the absolute WBCc of participants. The study suggests where resources are limited, use of assumed WBCc of 10.0 × 10(9)/L of blood to estimate malaria parasite density in central Ghana. Preferably, absolute WBCc should be used in drug efficacy and vaccine trials.</p>
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spelling doaj.art-d88088b26960406ab325149229ea2ce12022-12-22T01:20:22ZengBMCMalaria Journal1475-28752012-07-0111123810.1186/1475-2875-11-238Estimating malaria parasite density: assumed white blood cell count of 10,000/μl of blood is appropriate measure in Central GhanaAdu-Gyasi DennisAdams MohammedAmoako SabastinaMahama EmmanuelNsoh MaxwellAmenga-Etego SeebaBaiden FrankAsante KwakuNewton SamOwusu-Agyei Seth<p>Abstract</p> <p>Background</p> <p>White blood cells count (WBCc) is a bedrock in the estimation of malaria parasite density in malaria field trials, interventions and patient management. White blood cells are indirectly and relatively used in microscopy to estimate the density of malaria parasite infections. Due to frequent lack of facilities in some malaria-endemic countries, in order to quantify WBCc of patients, an assumed WBCc of 8.0 X 10(9)/L has been set by the World Health Organization to help in estimating malaria parasite densities.</p> <p>Methods</p> <p>This comparative analysis study, in Central Ghana, compiled laboratory data of 5,902 <it>Plasmodium falciparum</it> malaria parasite positive samples. Samples were obtained from consented participants of age groups less than five years. Full blood counts (FBC) of participants’ samples were analysed using the ABX Micros 60 Haematology Analyzer. Blood slides were read by two competent microscopists to produce concordant results. All internal and external quality control measures were carried out appropriately. Parasite densities were calculated using participants’ absolute WBCc and assumed WBCc of 5,000 to 10,000 per microlitre of blood.</p> <p>Results</p> <p>From the 5,902 Pf malaria positive samples, the mean (SD) WBCc and geometric mean parasite density were 10.4 (4.6) × 10(9)/L and 7,557/μL (95 % CI 7,144/μL to 7,994/μL) respectively. The difference in the geometric mean parasite densities calculated using absolute WBCs and compared to densities with assumed WBCs counts were significantly lower for 5.0 × 10(9)/L; 3,937/μL, 6.0 × 10(9)/L; 4,725/μL and 8.0 × 10(9)/L; 6,300/μL. However, the difference in geometric mean parasite density, 7,874/μL (95 % CI, 7,445/μL to 8,328/μL), with assumed WBCc of 10.0 × 10(9)/L was not significant.</p> <p>Conclusion</p> <p>Using the assumed WBCc of 8.0 X 10(9)/L or lower to estimate malaria parasite densities in Pf infected children less than five years old could result in significant underestimation of parasite burden. Assumed WBCc of 10.0 × 10(9)/L at 95 % CI of geometric mean of parasite density statistically agreed with the parasite densities produce by the absolute WBCc of participants. The study suggests where resources are limited, use of assumed WBCc of 10.0 × 10(9)/L of blood to estimate malaria parasite density in central Ghana. Preferably, absolute WBCc should be used in drug efficacy and vaccine trials.</p>http://www.malariajournal.com/content/11/1/238
spellingShingle Adu-Gyasi Dennis
Adams Mohammed
Amoako Sabastina
Mahama Emmanuel
Nsoh Maxwell
Amenga-Etego Seeba
Baiden Frank
Asante Kwaku
Newton Sam
Owusu-Agyei Seth
Estimating malaria parasite density: assumed white blood cell count of 10,000/μl of blood is appropriate measure in Central Ghana
Malaria Journal
title Estimating malaria parasite density: assumed white blood cell count of 10,000/μl of blood is appropriate measure in Central Ghana
title_full Estimating malaria parasite density: assumed white blood cell count of 10,000/μl of blood is appropriate measure in Central Ghana
title_fullStr Estimating malaria parasite density: assumed white blood cell count of 10,000/μl of blood is appropriate measure in Central Ghana
title_full_unstemmed Estimating malaria parasite density: assumed white blood cell count of 10,000/μl of blood is appropriate measure in Central Ghana
title_short Estimating malaria parasite density: assumed white blood cell count of 10,000/μl of blood is appropriate measure in Central Ghana
title_sort estimating malaria parasite density assumed white blood cell count of 10 000 μl of blood is appropriate measure in central ghana
url http://www.malariajournal.com/content/11/1/238
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