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Background: wrongs in experiments and laboratories are inevitable particularly if used non-standard methods and tools. In routine disc diffusion test used optical method for pouring media in petri dishes that create non negligible errors in experiments. Goal of this research is design and produce a standard petri dish for this tests and eliminate the wrongs.
Methods: According CLSI standards about sensitivity tests medium standard thickness is 4 millimeters. According these data designed a standard petri dish that determined this standard thickness exactly.
Results: Results of this research showed existing Petri dishes produce wrong and different reports about non-growth haloes even for identical antibiotics that cause to antibiotic unfit administration significantly (P<0.05). In addition, medium waste rate was 33-50% for different petri dishes.
Conclusion: Designed standard petri dish standardized disc diffusion tests and other sensitivity tests and makes accuracy, non- growth haloes uniformity in identical tests, and antibiotics fit choose. Also decrease medium waste rate significantly.