Revista Latinoamericana de Patología Clínica y Medicina de Laboratorio

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>Journals >Revista Latinoamericana de Patología Clínica y Medicina de Laboratorio >Year 2010, Issue 4

Westgard J, Mercapide L, Sáez A, Porras A, Martínez O, Amaya E, Iturriza M, Mendoza E, Brambila E, Terrés A
How to guarantee the analytic quality
Rev Latinoamer Patol Clin 2010; 57 (4)

Language: Español
References: 15
Page: 179-189
PDF: 329.56 Kb.

[Full text - PDF]


Background: On July, 2010 previous to the 5th International Cycle of Quality Conferences a number of experts from Latin America met in Cancun, Mexico including chemists, pathologists, and related professionals to discuss various topics on the current state of quality management and technical competence in clinical laboratory. The conclusions of this event was transmitted live to thirty-five alternate venues in Argentina, Brazil, Colombia, Chile, Ecuador, Panama, Peru, Dominican Republic, and Venezuela. The event was sponsored by Bio- Rad and counted with the recognition of IFCC and with the support of the Secretariat of Health of Mexico, in addition to multiple national professional societies from the participating countries. The main objective of the reunion was to review issues affecting Latin America on quality improvement of laboratories, notably: 1) Education and training professionals and technicians 2) Reinforcement in mandatory, regulations. 3) Improving economic resources. 4) Improvements in coordination between those involved. To perform this task the organizers distributed experts into five groups which covered the following topics: 1) How to achieve an appropriate and adequate quality in clinical laboratories. 2) Effective control of analytical stage 3) Education: pillar of quality on clinical laboratory. 4) Risks control on clinical laboratory: the critical staff role in patient care 5) Preparing clinical laboratory for crisis management. Lessons from AH1N1 flu epidemic. Objective: This document presents conclusions of Group 2, which dealt with the Effective Control of the Analytical Stage, emphasizing specific issues such as medical relevance, strategic planning of quality, internal quality control, external quality assessment, proficiency testing, traceability, uncertainty, and risk analysis. Method: During two journeys, experts reviewed international regulations and discussed specific issues, commenting on the situation from each of their seven countries of origin, including regulations and practices of each of them. The approach was eminently practical to give priority to the possibility of generating basic recommendations that may apply immediately to any clinical laboratory regardless of their medical care level, or geographic location regardless of whether these recommendations can evolve towards guidelines or standards in the future. The conclusions of each work group were presented on a plenary session with live transmission via Internet to the 34 sites of the above-mentioned countries. Original submissions are now available at https://bio-rad.on.intercall.com/ confmgr/public_stored_docs.jsp Recommendations: INTERNAL QUALITY CONTROL. Traceability is manufacturer’s responsibility, laboratory should request the documentation. Validation is a laboratory responsibility. Proper personnel should review and comply with manufacturer recommendations, but not only limit to them. The number, frequency and level controls depends on the number of tests and the magnitude of the analytical round; type test: manual or automated; the type of round (continuous flow or batch); the number of shifts per day and days of the week that performs test plus additional events such as batch change, calibrations, blackouts, etc. Each Head of the Laboratory must design and document a control plan. In general it may be recommended to locate a normal control and an abnormal at the beginning and end of the round (n = 4 controls) compare and assess the results. If you notice differences it is appropriate to add a couple at the mid point of the round. Evaluate the outcomes of patients by calculating the average and median of all the results that are within of reference limits. Note and also monitor the percentage of abnormal results. Perform a detailed statistical control of all data (controls and patients). EXTERNAL QUALITY ASSESSMENT. The Proficiency Test Provider must approve ILAC G13/08: 2007 / ISO 17043:2010 Standards. Uniformity and accuracy evaluation is the responsibility of the proficiency testing provider. The program must use unbiased high quality controls. The frequency must be at least monthly. The laboratory must retain an aliquot to make verifications. Report results must be within the first 72 hours so that appropriate measures can be applied. The most important for evaluating accuracy parameter is Bias % vs. Assigned Value. The laboratory must apply preventive and corrective measures utilizing independent «Third Opinion Controls» systematically. Discussion: The key point of evidence-based medicine is within the clinical laboratory, which generates the basis on which more than 70 % of medical decisions are taken. Medical relevance of clinical laboratory is the fundamental premise. Quality health care, from the point of view of efficiency, lies precisely in the clinical laboratory where the need for technical competence and quality management systems is clear; including traceable, well controlled and validated methods. The first step to achieve the quality is the elaboration of a strategic plan that shall include specific, measurable, achievable and challenging analytical objectives that actually are being developed worldwide on biological variation basis in order to achieve medical relevance.

Key words: Medical relevance, quality strategic plan, analytical quality control, internal quality control, proficiency testing, six sigma, traceability, validation, uncertainty, risk analysis.


  1. ISO 15189:2007 Laboratorios Clínicos. Requisitos Particulares para la Calidad y la Competencia.

  2. ISO 15198: Laboratorios De Análisis Clínicos. Dispositivos Para Diagnóstico In Vitro. Validación de las Recomendaciones del Proveedor para el Control de Calidad por parte del Usuario. .

  3. ILAC-G13:08/2007: Guidelines For The Requirements For The Competence Of Providers Of Proficiency Testing Schemes.

  4. ISO/IEC 17043:2010 Conformity assessment – General Requirements For Proficiency Testing.

  5. CLSI/NCCLS C24a3 Statistical Quality Control For Quantitative Measurement Procedures: Principles And Definitions; Approved Guideline.

  6. CLSI/NCCLS. Ep5-A2 Evaluation of Precision Performance of Quantitative Measurement Methods; Approved Guideline. 2nd Ed. Wayne, Pennsylvania: NCCLS, 2004.

  7. CLSI/NCCLS Ep23-P: Laboratory Quality Control Based on Risk Management.

  8. Westgard Jo, Groth T. Power Function Graphs For Statistical Control Rules. Clin Chem 1979; 25: 863-869.

  9. Westgard Jo, Burnett Rw. Precision Requirements For Cost- Effective Operation Of Analytical Processes. Clin Chem 1990; 36: 1629-1632.

  10. Westgard Jo. Charts Of Operating Specifications (Opspecs Charts) For Assessing The Precision, Accuracy, And Quality Control Needed To Satisfy Proficiency Testing Criteria. Clin Chem 1992; 38: 1226-1233.

  11. Westgard Jo. A Method Evaluation Decision Chart (Medx Chart) For Judging Method Performance. Clin Lab Science 1995; 8: 277- 283.

  12. Westgard Jo. Basic Method Validation. Chapter 12: The Decision On Method Performance In Basic Method Validation. Madison, Wi: Westgard Qc, Inc., 1999, Pages 125-134.

  13. Terrés SAM. Trazabilidad Metrológica, Validación Analítica y Consenso de Resultados en la Confiabilidad del Laboratorio Clínico. Rev Mex Patol Clin 2009; 56 (1).

  14. Terrés-Speziale AM. Importancia de la Variabilidad Biológica y de la Relevancia Médica En la Norma ISO-15189. Rev Mex Patol Clin 2003; 50 (3).

  15. Terrés-Speziale AM. Six Sigma. Determinación de Metas Analíticas con Base a la Variabilidad Biológica y la Evolución Tecnológica. Rev Mex Patol Clin 2007; 54 (1).

>Journals >Revista Latinoamericana de Patología Clínica y Medicina de Laboratorio >Year 2010, Issue 4

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