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Estimating the parasitaemia of Plasmodium falciparum: experience from a national EQA scheme.

Manser M, Olufsen C, Andrews N, Chiodini PL - Malar. J. (2013)

Bottom Line: An average of 25% of participants failed to estimate the percentage parasitaemia, 17% overestimated and 8% underestimated, whilst 5% misidentified the malaria species present.Although the results achieved by participants for other blood parasites have shown an overall improvement, the level of performance for estimation of the parasitaemia of P. falciparum remains unchanged over 15 years.Possible reasons include incorrect calculation, not examining the correct part of the film and not examining an adequate number of microscope fields.

View Article: PubMed Central - HTML - PubMed

Affiliation: UKNEQAS Parasitology, Department of Clinical Parasitology, Hospital for Tropical Diseases, Mortimer Market, Capper Street, London WC1E 6JB, UK. peter.chiodini@uclh.nhs.uk.

ABSTRACT

Background: To examine performance of the identification and estimation of percentage parasitaemia of Plasmodium falciparum in stained blood films distributed in the UK National External Quality Assessment Scheme (UKNEQAS) Blood Parasitology Scheme.

Methods: Analysis of performance for the diagnosis and estimation of the percentage parasitaemia of P. falciparum in Giemsa-stained thin blood films was made over a 15-year period to look for trends in performance.

Results: An average of 25% of participants failed to estimate the percentage parasitaemia, 17% overestimated and 8% underestimated, whilst 5% misidentified the malaria species present.

Conclusions: Although the results achieved by participants for other blood parasites have shown an overall improvement, the level of performance for estimation of the parasitaemia of P. falciparum remains unchanged over 15 years. Possible reasons include incorrect calculation, not examining the correct part of the film and not examining an adequate number of microscope fields.

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The range of parasitemia reported by participants on a blood film with an intended result of 11.4%.
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Figure 6: The range of parasitemia reported by participants on a blood film with an intended result of 11.4%.

Mentions: Figures 5,6 and7 give graphical illustrations of the range of percentage parasitaemia reported by participants in some of the specimens containing trophozoites of P. falciparum distributed. They demonstrate that all specimens were prone to overestimation, under estimation (although less so with low parasitaemia) and failure to estimate the percentage parasitaemia.


Estimating the parasitaemia of Plasmodium falciparum: experience from a national EQA scheme.

Manser M, Olufsen C, Andrews N, Chiodini PL - Malar. J. (2013)

The range of parasitemia reported by participants on a blood film with an intended result of 11.4%.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4222811&req=5

Figure 6: The range of parasitemia reported by participants on a blood film with an intended result of 11.4%.
Mentions: Figures 5,6 and7 give graphical illustrations of the range of percentage parasitaemia reported by participants in some of the specimens containing trophozoites of P. falciparum distributed. They demonstrate that all specimens were prone to overestimation, under estimation (although less so with low parasitaemia) and failure to estimate the percentage parasitaemia.

Bottom Line: An average of 25% of participants failed to estimate the percentage parasitaemia, 17% overestimated and 8% underestimated, whilst 5% misidentified the malaria species present.Although the results achieved by participants for other blood parasites have shown an overall improvement, the level of performance for estimation of the parasitaemia of P. falciparum remains unchanged over 15 years.Possible reasons include incorrect calculation, not examining the correct part of the film and not examining an adequate number of microscope fields.

View Article: PubMed Central - HTML - PubMed

Affiliation: UKNEQAS Parasitology, Department of Clinical Parasitology, Hospital for Tropical Diseases, Mortimer Market, Capper Street, London WC1E 6JB, UK. peter.chiodini@uclh.nhs.uk.

ABSTRACT

Background: To examine performance of the identification and estimation of percentage parasitaemia of Plasmodium falciparum in stained blood films distributed in the UK National External Quality Assessment Scheme (UKNEQAS) Blood Parasitology Scheme.

Methods: Analysis of performance for the diagnosis and estimation of the percentage parasitaemia of P. falciparum in Giemsa-stained thin blood films was made over a 15-year period to look for trends in performance.

Results: An average of 25% of participants failed to estimate the percentage parasitaemia, 17% overestimated and 8% underestimated, whilst 5% misidentified the malaria species present.

Conclusions: Although the results achieved by participants for other blood parasites have shown an overall improvement, the level of performance for estimation of the parasitaemia of P. falciparum remains unchanged over 15 years. Possible reasons include incorrect calculation, not examining the correct part of the film and not examining an adequate number of microscope fields.

Show MeSH
Related in: MedlinePlus