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Systematic comparison of two methods to measure parasite density from malaria blood smears.

Publication ,  Journal Article
Prudhomme O'Meara, W; Remich, S; Ogutu, B; Lucas, M; Mtalib, R; Obare, P; Oloo, F; Onoka, C; Osoga, J; Ohrt, C; McKenzie, FE
Published in: Parasitol Res
September 2006

This study was designed to directly compare the accuracy, reproducibility, and efficiency of three methods commonly used to measure blood-stage malaria parasite density from Giemsa-stained blood films. Parasites and white blood cells (WBCs) were counted in 154 thick films by two independent microscopists. Forty-six slides were read by counting parasitized red blood cells (RBCs) in the thin film. Using these same slides, parasites were again counted by two independent microscopists using an ocular grid. Overall, parasite densities were significantly lower and discrepancy between readers was higher when using the grid method compared to the WBC method, but there was no difference when compared to the RBC method. When one reader who had difficulty with the grid method was excluded, the discrepancy between readers was equivalent for the three methods. Densities and discrepancy between readers were indistinguishable when parasites were counted until 200 or 500 WBCs. Counting beyond 200 WBCs may not significantly improve parasite density measurements. Using an ocular grid directly measures parasites per volume rather than using a WBC per microliter conversion factor and eliminates the need to switch from the thick film to the thin film for high parasitemias. However, significant differences in densities measured by the grid method and the WBC method need to be evaluated.

Duke Scholars

Published In

Parasitol Res

DOI

ISSN

0932-0113

Publication Date

September 2006

Volume

99

Issue

4

Start / End Page

500 / 504

Location

Germany

Related Subject Headings

  • Reproducibility of Results
  • Plasmodium falciparum
  • Mycology & Parasitology
  • Microscopy
  • Malaria, Falciparum
  • Leukocyte Count
  • Erythrocyte Count
  • Azure Stains
  • Animals
  • 3207 Medical microbiology
 

Citation

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Prudhomme O’Meara, W., Remich, S., Ogutu, B., Lucas, M., Mtalib, R., Obare, P., … McKenzie, F. E. (2006). Systematic comparison of two methods to measure parasite density from malaria blood smears. Parasitol Res, 99(4), 500–504. https://doi.org/10.1007/s00436-006-0135-x
Prudhomme O’Meara, Wendy, Shon Remich, Bernhards Ogutu, Martin Lucas, Ramadan Mtalib, Peter Obare, Frederick Oloo, et al. “Systematic comparison of two methods to measure parasite density from malaria blood smears.Parasitol Res 99, no. 4 (September 2006): 500–504. https://doi.org/10.1007/s00436-006-0135-x.
Prudhomme O’Meara W, Remich S, Ogutu B, Lucas M, Mtalib R, Obare P, et al. Systematic comparison of two methods to measure parasite density from malaria blood smears. Parasitol Res. 2006 Sep;99(4):500–4.
Prudhomme O’Meara, Wendy, et al. “Systematic comparison of two methods to measure parasite density from malaria blood smears.Parasitol Res, vol. 99, no. 4, Sept. 2006, pp. 500–04. Pubmed, doi:10.1007/s00436-006-0135-x.
Prudhomme O’Meara W, Remich S, Ogutu B, Lucas M, Mtalib R, Obare P, Oloo F, Onoka C, Osoga J, Ohrt C, McKenzie FE. Systematic comparison of two methods to measure parasite density from malaria blood smears. Parasitol Res. 2006 Sep;99(4):500–504.
Journal cover image

Published In

Parasitol Res

DOI

ISSN

0932-0113

Publication Date

September 2006

Volume

99

Issue

4

Start / End Page

500 / 504

Location

Germany

Related Subject Headings

  • Reproducibility of Results
  • Plasmodium falciparum
  • Mycology & Parasitology
  • Microscopy
  • Malaria, Falciparum
  • Leukocyte Count
  • Erythrocyte Count
  • Azure Stains
  • Animals
  • 3207 Medical microbiology