title: Stage determination in sleeping sickness: comparison of two cell counting and two parasite detection techniques.
abstract: OBJECTIVE
  Diagnosis of the neurological stage of human African trypanosomiasis is performed by examination of cerebrospinal fluid (CSF) for the presence of trypanosomes and numbers of white blood cells (WBC). Both CSF parameters are also used to assess treatment outcome during follow-up. In view of the importance of CSF examination, and the practical problems encountered with it, we compared the sensitivity of two trypanosome concentration techniques and the repeatability of two cell counting methods, as well as occurrence of systematic differences between them.
  
  
  METHODS
  Patients were recruited at Dipumba hospital, in Mbuji-Mayi in the Democratic Republic of the Congo. In 94 CSF samples, trypanosome detection was performed with modified single centrifugation (MSC) and double centrifugation (DC). On 189 CSF samples with ≤30 cells/μl, cell counting was performed in duplicate in a Fuchs-Rosenthal counting chamber and in a disposable Uriglass counting chamber.
  
  
  RESULTS
  Modified single centrifugation detected trypanosomes in significantly (P < 0.0001) more patients (85) than DC (46). Cell counts did not differ systematically in the two methods. Variability in the differences between duplicate cell counts was significantly higher (P = 0.002) in Uriglass (SD of differences 2.03) than in Fuchs-Rosenthal (SD of differences 1.62).
  
  
  CONCLUSIONS
  For analysis of CSF in the context of sleeping sickness stage determination and follow-up after treatment, we strongly recommend the MSC for parasite detection and the application of disposable counting chambers. When the first cell count is ≤20 cells/μl, we recommend repeating the counting procedure on the same CSF specimen and taking the average of both countings.
authors.affiliation: Institut National de Recherche Biomédicale, Kinshasa Gombe, Democratic Republic of the Congo.
authors.forename: Dieudonné
authors.initials: D
authors.lastname: Mumba Ngoyi
authors.forename: Joris
authors.initials: J
authors.lastname: Menten
authors.forename: Pati Patient
authors.initials: PP
authors.lastname: Pyana
authors.forename: Philippe
authors.initials: P
authors.lastname: Büscher
authors.forename: Veerle
authors.initials: V
authors.lastname: Lejon
mesh_terms: D002555:Cerebrospinal Fluid / Q000469:parasitology*; D015023:Democratic Republic of the Congo; D006801:Humans; D007958:Leukocyte Count; D007962:Leukocytes / Q000469:parasitology*; D012015:Reference Standards; D014347:Trypanosoma brucei gambiense / Q000302:isolation & purification*; D014353:Trypanosomiasis, African / Q000134:cerebrospinal fluid* / Q000145:classification*