title: Proficiency testing assessments for nematode worm egg counting based on Poisson variation.
abstract: The Poisson distribution provides an appropriate model for the variation within laboratories in worm egg counting. This is demonstrated by the results from annual quality assessment exercises in which laboratories in Australia tested multiple samples from the same mixtures prepared using different worm egg densities. Confidence intervals based on simulations using the Poisson distribution are recommended in the analysis of the results to identify laboratories showing significant bias or overdispersion, hence indicating possible procedural errors.
authors.affiliation: Department of Agriculture and Food, 444 Albany Highway, Albany 6330, WA, Australia. Electronic address: andrew.vanburgel@agric.wa.gov.au.
authors.forename: A J
authors.initials: AJ
authors.lastname: van Burgel
authors.affiliation: Department of Agriculture and Food, 444 Albany Highway, Albany 6330, WA, Australia.
authors.forename: J
authors.initials: J
authors.lastname: Lyon
authors.affiliation: Department of Agriculture and Food, 444 Albany Highway, Albany 6330, WA, Australia.
authors.forename: R B
authors.initials: RB
authors.lastname: Besier
authors.affiliation: Animal Health Laboratories, Department of Agriculture and Food, 3 Baron Hay Court, South Perth 6151, WA, Australia.
authors.forename: D G
authors.initials: DG
authors.lastname: Palmer
mesh_terms: D000818:Animals; D001315:Australia / Q000453:epidemiology; D005243:Feces / Q000469:parasitology; D006374:Helminthiasis, Animal / Q000453:epidemiology* / Q000469:parasitology; D006376:Helminths / Q000302:isolation & purification*; D010270:Parasite Egg Count / Q000662:veterinary; D016012:Poisson Distribution; D012756:Sheep; D012757:Sheep Diseases / Q000453:epidemiology* / Q000469:parasitology
keywords: Faecal egg count; Laboratory; Poisson distribution; Proficiency testing; Quality assurance; Worm egg count