title: An image analysis system: an objective and accurate alternative for reading the agar diffusion test.
abstract: A computerized image analysis system (IAS) has been used to develop a new method for reading the agar diffusion test automatically. In four experiments a total of 88 porcine plasma and 95 urine samples were screened for oxytetracycline by the agar diffusion test. The inhibition zones were measured by hand and by the IAS directly from the bioassay plate and by the IAS from the photo-negative taken from the plate. Both methods were positively correlated with the hand method for plasma (0.9716, 0.9669) and urine (0.9878, 0.9731) in the range tested for 0.1 to 2.0 micrograms/ml. Moreover, the coefficient of variation and the day-to-day-variation amounted to 1.72% and 1.47% respectively, for the method by hand and 1.10, 1.54% and 0.27, 0.38% respectively, for the IAS methods. It is concluded that the IAS method is an objective and accurate alternative for reading the agar diffusion test.
authors.affiliation: Department of Herd Health and Reproduction, College of Veterinary Medicine, University of Utrecht, The Netherlands.
authors.forename: E J
authors.initials: EJ
authors.lastname: Schoevers
authors.forename: M
authors.initials: M
authors.lastname: Terlou
authors.forename: A
authors.initials: A
authors.lastname: Pijpers
authors.forename: J H
authors.initials: JH
authors.lastname: Verheijden
mesh_terms: D000362:Agar; D000818:Animals; D001681:Biological Assay / Q000662:veterinary; D005240:Feasibility Studies; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D005779:Immunodiffusion / Q000379:methods / Q000662:veterinary*; D010118:Oxytetracycline / Q000097:blood* / Q000652:urine; D013552:Swine / Q000097:blood* / Q000652:urine
chemical_list: D000362:Agar; D010118:Oxytetracycline