Bulletin of the World Health Organization

External quality assessment of Giemsa-stained blood film microscopy for the diagnosis of malaria and sleeping sickness in the Democratic Republic of the Congo

Pierre Mukadi, Philippe Gillet, Albert Lukuka, Benjamin Atua, Nicole Sheshe, Albert Kanza, Jean Bosco Mayunda, Briston Mongita, Raphaël Senga, John Ngoyi, Jean-Jacques Muyembe, Jan Jacobs & Veerle Lejon

Volume 91, Number 6, June 2013, 441-448

Table 1. Sample analysis, external quality assessment of laboratories, Democratic Republic of the Congo, 2011

Samplea Information accompanying sample No. of laboratories reporting No. of laboratory reports that contained:
No error Minor error Major error
Slide 1: P. falciparum gametocytes 14-year-old patient with fever, abdominal pain, asthenia and diarrhoea  268 120 97 (Plasmodium infection not reported) 47 (Plasmodium infection reported but the developmental stage was not reported or incorrect) 
4 (gametocytes reported but no or wrong species identified)
Slide 2: no parasites 39-year-old patient, control visit 269 218 51 (Plasmodium infection reported)
Slide 3: Trypanosoma brucei ssp. Sample received at Institut National de Recherche Biomédicale for scientific research 270 120 14 (both Plasmodium and Trypanosoma infection reported) 136 (Trypanosoma infection not reported)
Slide 4: P. falciparum trophozoites (density: 113 530 per µl)  44-year-old patient with general weakness, asthenia and headache 271 37 23 (reported P. falciparum infection but not developmental stage) 5 (Plasmodium infection not reported)
103 (trophozoite density moderately below reference value)b 30 (wrong or no species reported)
14 (trophozoite density moderately above reference range)b 6 (P. falciparum gametocytes reported)
21 (no trophozoite density reported) 30 (trophozoite density well below reference range)b
2 (trophozoite density well above reference range)b

P. falciparum, Plasmodium falciparum; SD, standard deviation; ssp., subspecies.

a Giemsa-stained thick and thin blood films.

b A reported trophozoite density within the reference range of 63 000 to 164 000 per μl (e.g. within 2 SDs of the reference value of 113 530 trophozoites per µl) was considered correct; a density between 11 353 and 62 999 per µl was moderately below the reference range; a density between 164 001 and 1 135 3-00 per µl was moderately above; a density of < 11 353 per µl was well below; and a density of > 1 135 300 per µl was well above.