Measurement uncertainty evaluation and risk of false conformity assessment for microbial enumeration tests

Autor(es)

Dias, Francielle Regina Silva ^[1] ; Lourenco, Felipe Rebello ^[1]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Fac Pharmaceut Sci, Dept Pharm, Sao Paulo - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Journal of Microbiological Methods; v. 189, OCT 2021.
• Citações Web of Science: 0

Resumo

Microbial enumeration tests are widely used to assess the microbiological quality of non-sterile pharmaceutical products. Despite of all efforts to guarantee the reliability of microbial enumeration tests, there will always be an uncertainty associated with the measured values, which can lead to false conformity/non-conformity decisions. In this work, we evaluated the measurement uncertainty using a bottom-up approach and estimate the consumer's or producer's risk due to the measurement uncertainty. Three main sources of uncertainty were identified and quantified: dilution factor, plated volume, and microbial plate counts. The contribution of these sources of uncertainty depends on the measured value of microbial load in pharmaceutical products. The contribution of dilution factor and plated volume uncertainties increase with an increase of measured value, while the contribution of microbial plate count uncertainty decreases with an increase of measured value. The overall uncertainty values were expressed as uncertainty factors, which provide an asymmetric 95% level confidence level of microbial load in pharmaceutical products. In addition, the risk of false conformity/nonconformity decisions due to measurement uncertainty was assess using Monte Carlo method. When the measured value is close to the upper specification limit and/or the measurement uncertainty is large, the risk of false conformity/non-conformity decisions may be significantly high. Thus, we conclude that the use of uncertainty factor in the conformity/non-conformity assessment is important to guarantee the reliability of microbial enumeration test results and to support decision-making. (AU)

• Processo FAPESP: 19/16206-3 - Riscos de decisões falsas quanto a avaliação de equivalência farmacêutica devido as incertezas de medições
• Beneficiário: Felipe Rebello Lourenço
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 17/04539-2 - Aplicação da incerteza de medição na avaliação de desempenho de métodos analíticos
• Beneficiário: Felipe Rebello Lourenço
• Modalidade de apoio: Auxílio à Pesquisa - Regular