Evaluation of the Use of Microtracers™ in a Proficiency Testing Program

Abstract

Background: An effective proficiency testing program must utilize accurate splitting procedures to ensure that customers receive equivalent (by some measure) test items. When test items are not equivalent, it becomes impossible to separate variation among laboratories from variation among test items, and the program cannot achieve its objectives. Therefore, there is a critical need to validate the splitting process used to manufacture test items. Objective: The incorporation of MicrotracersTM was investigated for validating the splitting process used in the Association of American Feed Control Officials Proficiency Testing Program and as a potential quality control event for a production run. Methods: Microtracers were incorporated into six production runs. From each run, 12 test items were randomly selected for evaluation. Proficiency test materials were prepared from commercially available feedstuffs using base animal feeds and feed additives. The tracers were incorporated into base feed with other additives, recovered, and counted from the randomly selected test items. Results: Uniformity of test items was evaluated with the following two statistical methods: (1) relative standard deviation (RSD) of particle counts according to a Poisson distribution and (2) a Pearson’s Chi-square test. RSDs for counts (per mass basis) ranged from 2.49 to 4.13%, and Chi-square P values ranged from 0.0097 to 0.3740 over the six sets. Conclusions: Microtracers were determined to be a potential tool for validating the splitting process used to manufacture proficiency test items and a tool for incorporating quality control events into the manufacture of proficiency test items. Highlights: The authors offer suggestions for proficiency testing programs.

Predicting the excretion of feces, urine and nitrogen using support vector regression: A case study with Holstein dry cows

“…During the formal trial period, the daily diets and residual samples were collected and determined, and the average intakes of dry matter and nutrients in the diets were calculated by the difference between the amount of inputs and residues of the daily diets. The contents of dry matter (DM), crude ash (Ash), ether extract (EE), crude protein (CP), and lignin (LIGNIN) were determined by the standard method of AOAC [34] , neutral detergent fiber (NDF), acid detergent fiber (ADF), acid detergent lignin (ADL), neutral detergent insoluble crude protein (NDICP), and acid detergent insoluble crude protein (ADICP) by Van Soest et al [35] , non-protein nitrogen (NPN) by Licitra et al [36] , crude protein (SCP) by Krishnamoorthy et al [37] , and starch by Karkalas [38] . In addition, According to the standards of CNCPS, the contents of various components of carbohydrates and proteins (PA, PB1, PB2, PB3, PC, CA, CB1, CB2, and CC) were calculated by the method of Sniffen et al [39] .…”

Avaliação Da Efetividade De Participações Em Programas De Ensaio De Proficiência No Controle Da Qualidade Dos Resultados Analíticos Na Determinação De Metais E Semimetais Em Águas Em Laboratório De Saúde Pública

“…Assim, com intuito de melhorar a competividade, bem como a emissão de resultados confiáveis dos laboratórios participantes a seus clientes, a literatura recente disponibiliza importantes avaliações críticas de Provedores de Ensaios de Proficiência em suas áreas de atuação, onde são apresentadas as evidências de progresso, bem como são abordadas as dificuldades na implantação e manutenção das rodadas (16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29).…”