Conformity Decisions Based on Measurement Uncertainty—a Case Study Applied to Agar Diffusion Microbiological Assay

  • Luciana Separovic
  • Maria Luiza de Godoy Bertanha
  • Alessandro Morais Saviano
  • Felipe Rebello LourençoEmail author
Original Article



Antimicrobial activity of drug products containing antibiotics is often measured using microbiological assays. However, the high values of measurement uncertainty associated with the analytical results obtained from microbiological assays may be an issue to conformity decisions.


The aim of this work was to estimate the risk of false decisions in conformity assessment due to measurement uncertainty for the potency of apramycin in pharmaceutical drug products. Monte Carlo method (MCM) simulations were performed in order to estimate global consumers’ (Rc) and producers’ (Rp) risks using a Bayesian approach and specific consumers’ (Rc) and producers’ (Rp) risks using a frequentist approach.


Despite of the high value of measurement uncertainty, Rc and Rp were found to be 0.0% and 0.3%, respectively. However, Rc and Rp were found to be high when the analytical result is close to the specification limits. Risk estimation using Bayesian approach is recommended to be applied by manufacturers, while frequentist approach may be an alternative to regulatory and third-party laboratories.


Measurement uncertainty Conformity assessment Risk of false decisions Microbiological assay Monte Carlo method (MCM) 


Funding Information

This study was funded by FAPESP - Fundação de Amparo à Pesquisa do Estado de São Paulo (2016/04100-8 and 2017/04539-2) and CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior.

Compliance with Ethical Standards

Conflict of Interest

The authors declare that they have no conflict of interest.


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Copyright information

© Springer Science+Business Media, LLC, part of Springer Nature 2019

Authors and Affiliations

  1. 1.Departamento de Farmácia, Faculdade de Ciências FarmacêuticasUniversidade de São PauloSão PauloBrazil

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