Posted by James O. Westgard, PhD
Measurement Uncertainty in Screening Immunoassays in Blood Establishments
A PhD Thesis by Paulo Antonio Rodriques Pereira, December 2015, Universidade Catolica Portuguesa Porto, Escola Superior de Biuotecnologias
It was a pleasure to serve on the thesis jury June 15, 2016, for Dr. Paulo Pereira’s research on applications of Measurement Uncertainty to immunoassays used in screening blood products. Dr. Pereira is the Coordinator of the Quality Management Department of the Blood, Cells and Tissues Establishment, Instituto Portugues do Sangue e da Transplantacao (IPST), Lisboa, with responsibilities for the development, implementation, and maintenance of the quality management system for fulfilling ISO 9001 requirements, regulatory law of blood establishments, European Directives and other ISO guidelines. The IPST is an organization focused in blood and transplant areas and in their regulation. It has some 670 employees in 3 regions and a national department.
The thesis provided an overview and summary of several published papers that are available electronically:
- Pereria P, Magnusson B, Theordorsson E, Westgard J, Encarnacao P. Measurement uncertainty as a tool for evaluating the “grey-zone” to reduce the false negatives in immunochemical screening of blood donors for infectious diseases. Accreditation and Quality Assurance. First Online: November 15, 2015, DOI: 10.10007/s00769-015-1180-x.
- Pereira P, Westard J, Sghatchian J, de Sousa G. Quality management in the European screening laboratories in blood establishments: a view on current approaches and trends. Transfusion and Apheresis Science, 2015;52(2):245-251, DOI: 10.1016/j.transci.2015.02.014
- Pereira P, Westgard J, Encaracao P, Seghatchian J, de Soursa G. The role of uncertainty in results of screening immunoassays in blood establishments. Transfusion and Apheresis Science, 2015;52(2):252-255, DOI: 10.1016/j.transci.2015.02.015
- Pereira P, Westgard J, Encaracao P, Seghatchian J. Evaluation of the measurement uncertainty in screening immunoassays in blood establishments: Computation of diagnostic accuracy models. Transfusion and Apheresis Science, 2015;52(1):35-41, DOI: 10.1016/j.transci.2014.12.017
- Pereira P, Westgard J, Encaracao P, Seghatchian J, de Soursa G. Scheme for the selection of measurement uncertainty models in blood establishments’ screening immunoassays. Transfusion and Apheresis Science, 2015;52(1):42-47, DOI: 10.1016/j.transci.2014.12.018
- Pereira P, Westgard J, Encaracao P, Seghatchian J. Analytical model for calculating indeterminate results interval of screening tests, the effect on seroconversion window period: a brief evaluation of the impact of uncertain results on the blood establishment budget. Transfusion and Apheresis Science, 2014;51(2):126-31, DOI: 10.1016/j.transci.2014.10.004
This is an extensive amount of work, especially considering the difficulties of translating metrologic concepts and clinical chemistry quality management practices to the world of Blood Banks.
Dr. Pereira brings an interesting perspective to laboratory quality management. He views the Blood Bank as a “manufacturer” of blood products and applies MU to the whole production process, what we typically think of as the Total Testing Process. But, rather than report MU to the user or consumer (which is the recommendation for medical laboratories), he builds MU into the process to improve the safety of the blood product. For example, he considers the seroconversion window as a source of uncertainty that must be determined in order to produce a safe blood product. Normally, we don’t consider such a variable as part of the uncertainty of a measurement, but it certainly is a factor that affects the safety of a blood product. Likewise, the actual MU at the cutoff is determined and subtracted from the cutoff to identify a “gray zone” or indeterminate result, rather than reporting such MU to the user or consumer. In this way, uncertainty factors can be used to improve the production process, rather than confuse the user or consumer by reporting MU. That’s an important lesson for all of us if MU is to become useful for quality management in medical laboratories, rather than just an ISO accreditation requirement.
Congratulations, Dr. Pereira.