title: Assessing stool quantities generated by three specific Kato-Katz thick smear templates employed in different settings.
abstract: BACKGROUND
  The Kato-Katz technique is recommended for the diagnosis of helminth infections in epidemiological surveys, drug efficacy studies and monitoring of control interventions. We assessed the comparability of the average amount of faeces generated by three Kato-Katz templates included in test kits from two different providers.
  
  
  METHODS
  Nine hundred Kato-Katz thick smear preparations were done; 300 per kit. Empty slides, slides plus Kato-Katz template filled with stool and slides plus stool after careful removal of the template were weighed to the nearest 0.1 mg. The average amount of stool that was generated on the slide was calculated for each template, stratified by standard categories of stool consistency (i.e. mushy, soft, sausage-shaped, hard and clumpy).
  
  
  RESULTS
  The average amount of stool generated on slides was 40.7 mg (95 % confidence interval (CI): 40.0-41.4 mg), 40.3 mg (95 % CI: 39.7-40.9 mg) and 42.8 mg (95 % CI: 42.2-43.3 mg) for the standard Vestergaard Frandsen template, and two different templates from the Chinese Center for Disease Control and Prevention (China CDC), respectively. Mushy stool resulted in considerably lower average weights when the Vestergaard Frandsen (37.0 mg; 95 % CI: 34.9-39.0 mg) or new China CDC templates (37.4 mg; 95 % CI: 35.9-38.9 mg) were used, compared to the old China CDC template (42.2 mg; 95 % CI: 40.7-43.7 mg) and compared to other stool consistency categories.
  
  
  CONCLUSIONS
  The average amount of stool generated by three specific Kato-Katz templates was similar (40.3-42.8 mg). Since the multiplication factor is somewhat arbitrary and small changes only have little effect on infection intensity categories, it is suggested that the standard multiplication factor of 24 should be kept for the calculation of eggs per gram of faeces for all investigated templates.
authors.affiliation: Swiss Tropical and Public Health Institute, P.O. Box, CH-4002, Basel, Switzerland.|University of Basel, P.O. Box, CH-4003, Basel, Switzerland.|Exercise Physiology Lab, Institute of Human Movement Sciences and Sport, ETH Zurich, Winterthurerstrase 190, CH-8057, Zurich, Switzerland.
authors.forename: Andrea
authors.initials: A
authors.lastname: Leuenberger
authors.affiliation: Bagamoyo Research and Training Centre, Bagamoyo District Hospital, Ifakara Health Institute, P.O. Box 74, Bagamoyo, United Republic of Tanzania.
authors.forename: Tatu
authors.initials: T
authors.lastname: Nassoro
authors.affiliation: Swiss Tropical and Public Health Institute, P.O. Box, CH-4002, Basel, Switzerland.|University of Basel, P.O. Box, CH-4003, Basel, Switzerland.|Bagamoyo Research and Training Centre, Bagamoyo District Hospital, Ifakara Health Institute, P.O. Box 74, Bagamoyo, United Republic of Tanzania.
authors.forename: Khadija
authors.initials: K
authors.lastname: Said
authors.affiliation: Swiss Tropical and Public Health Institute, P.O. Box, CH-4002, Basel, Switzerland.|University of Basel, P.O. Box, CH-4003, Basel, Switzerland.|Institute of Social and Preventive Medicine, University of Bern, Finkenhubelweg 11, CH-3012, Bern, Switzerland.
authors.forename: Lukas
authors.initials: L
authors.lastname: Fenner
authors.affiliation: Ifakara Health Institute, Off Mlabani Passage, P.O. Box 53, Ifakara, United Republic of Tanzania.
authors.forename: George
authors.initials: G
authors.lastname: Sikalengo
authors.affiliation: Swiss Tropical and Public Health Institute, P.O. Box, CH-4002, Basel, Switzerland.|University of Basel, P.O. Box, CH-4003, Basel, Switzerland.|Ifakara Health Institute, Off Mlabani Passage, P.O. Box 53, Ifakara, United Republic of Tanzania.
authors.forename: Emilio
authors.initials: E
authors.lastname: Letang
authors.affiliation: Department of Control of Neglected Tropical Diseases, World Health Organization, Avenue Appia 20, CH-1211, Geneva 27, Switzerland.
authors.forename: Antonio
authors.initials: A
authors.lastname: Montresor
authors.affiliation: Chinese Center for Disease Control and Prevention, National Institute of Parasitic Diseases, 207 Rui Jin Er Road, Shanghai, 200025, People's Republic of China.|Key Laboratory on Biology of Parasite and Vector, Ministry of Health, WHO Collaborating Center for Malaria, Schistosomiasis and Filariasis, 207 Rui Jin Er Road, Shanghai, 200025, People's Republic of China.
authors.forename: Xiao-Nong
authors.initials: XN
authors.lastname: Zhou
authors.affiliation: Swiss Tropical and Public Health Institute, P.O. Box, CH-4002, Basel, Switzerland.|University of Basel, P.O. Box, CH-4003, Basel, Switzerland.
authors.forename: Peter
authors.initials: P
authors.lastname: Steinmann
authors.affiliation: Swiss Tropical and Public Health Institute, P.O. Box, CH-4002, Basel, Switzerland.|University of Basel, P.O. Box, CH-4003, Basel, Switzerland.
authors.forename: Hanspeter
authors.initials: H
authors.lastname: Marti
authors.affiliation: Swiss Tropical and Public Health Institute, P.O. Box, CH-4002, Basel, Switzerland.|University of Basel, P.O. Box, CH-4003, Basel, Switzerland.
authors.forename: Jürg
authors.initials: J
authors.lastname: Utzinger
authors.affiliation: Swiss Tropical and Public Health Institute, P.O. Box, CH-4002, Basel, Switzerland. s.knopp@unibas.ch.|University of Basel, P.O. Box, CH-4003, Basel, Switzerland. s.knopp@unibas.ch.|Wolfson Wellcome Biomedical Laboratories, Department of Life Sciences, Natural History Museum, Cromwell Road, London, SW7 5BD, United Kingdom. s.knopp@unibas.ch.
authors.forename: Stefanie
authors.initials: S
authors.lastname: Knopp
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D005243:Feces / Q000469:parasitology*; D006373:Helminthiasis / Q000175:diagnosis* / Q000453:epidemiology / Q000469:parasitology; D006801:Humans; D007753:Laboratories / Q000592:standards; D008875:Middle Aged; D010270:Parasite Egg Count / Q000295:instrumentation; D010274:Parasitology / Q000295:instrumentation / Q000379:methods*; D013557:Switzerland; D013636:Tanzania; D055815:Young Adult
keywords: Accuracy; Diagnosis; Infection intensity; Kato-Katz technique; Schistosomes; Soil-transmitted helminths