Revista Latinoamericana de Patología Clínica y Medicina de Laboratorio

Contents by Year, Volume and Issue

Table of Contents

General Information

Instructions for Authors

Message to Editor

Editorial Board

>Journals >Revista Latinoamericana de Patología Clínica y Medicina de Laboratorio >Year 2010, Issue 3

Terrés-Speziale AM
To improve the quality to level Six Sigma composing the results of the external assessment with the internal program applying the QQCDC method
Rev Latinoamer Patol Clin 2010; 57 (3)

Language: Español
References: 5
Page: 110-121
PDF: 155.35 Kb.

[Full text - PDF]


Background: ISO 15189: 2003 Standard was developed to improve Quality Management and Technical Competence to ensure that Clinical Laboratories report medically relevant results and to facilitate medical decisions based on evidence. In accordance with ISO, clinical Labs must have a responsible professional to 1) Warranty that the laboratory applies «IQCP» Internal Quality Control Program. 2) Participate on a Proficiency Testing Scheme which is recognized through the fulfillment of international standards specifically developed for External Quality Assessment Schemes «EQAS». 3) Satisfies the evaluation of each of the included trials. 4) Develops a well-documented methodology to solve problems where quality is not satisfactory. Standard ILAC G13:08/2007 was created by the International Laboratory Accreditation Cooperation to regulate Proficiency Programs, where 1) It is the provider’s responsibility of the External Quality Assessment Schemes to give advice to the participating laboratories and, 2) It is the responsibility of Labs to immediately correct the non-compliant results. Objective: To describe a practical and systematic method through which clinical laboratories can apply to reach a «Zero Error Level» through Six Sigma analytical reliability on the basis of non-compliant results detection, during External Quality Assessment Programs. Material and method: «Five Ws» method allows laboratory professionals to identify what, why, who, when, where has to be accomplished to report reliable and timely efficient results up to the Six Sigma level. It consists of several and well structured sequential steps where the goal is to calculate the Total Error before corrective and preventive measures are applied on the basis of the non-compliant results observed on Proficiency Testing and the evaluation of imprecision on the Internal Quality Control Program. Data evaluation should be done with results obtained during six cycles at least, applying linear regression and coefficient of correlation calculation in order to finally recalibrate tests and to verify results using Third Opinion Controls. Results: Measures generally recommended to improve performance are: 1) Strictly follow instructions for control preparation including accurate dilution volume, temperature and incubation time. 2) Keep a aliquot in optimal conditions to verify non-compliant results. 3) Review preventive and corrective maintenance frequently including water quality and electric power stability. 4) Review report units that are used on EQAS and standardize them with the IQCP. 5) On non compliant analytes from EQAS check all data that have previously been obtained on previous rounds by comparing all the values reported by the laboratory with all the assigned values for each round. On this basis regression calculation can estimate the correlation coefficient, the intercept and slope. 6) Re-calibrate using the multilevel paired calibrators while considering EQAS data. 7) Confirm accuracy using Third Opinion independent quality control specimens with global and specific method assigned values. Recommendations should be applied the recommendations immediately when a single result is not compliant, and when two results are in alert level even though non-consecutive. It is important to remember that precision depends on good maintenance of the equipment and must be controlled on the IQCP and that accuracy depends on good calibration and checks at the EQAS. Precision and Accuracy and must be well documented in the IQCP and EQAS in order to calculate Total Error. Conclusion: Evidence-based medicine depends on reliability and relevance of clinical laboratory data that must be under the control of an in-house quality program with the Support of External Quality Assessment Providers using scientifically valid methods and procedures.

Key words: Accreditation, ISO 15189:2007, ILAC G13:08/2007, medical relevance, biological variability, analytical variability.


  1. NORMA ISO/IEC 15189:2003. Laboratorios Clínicos - Requisitos Particulares para la Calidad y la Competencia.

  2. NORMA ISO/IEC 43-2:1997, Prueba de Aptitud por Comparaciones entre Laboratorios - Parte 2: Selección y Uso de los Esquemas de Evaluación Externa de la Calidad por los Cuerpos de la Acreditación del Laboratorio.

  3. NORMA ILAC-G13:08/2007 Requisitos para Proveedores de Ensayos de Aptitud o Esquemas de Evaluación Externa de la Calidad.

  4. Terrés Speziale AM. Six Sigma: determinación de metas analíticas con base en la variabilidad biológica y la evolución tecnológica. Rev Mex Patol Clin 2007; 54 (1): 28-39.

  5. 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) 118-128.

>Journals >Revista Latinoamericana de Patología Clínica y Medicina de Laboratorio >Year 2010, Issue 3

· Journal Index 
· Links 
Copyright 2010