title: Importance of implementing an analytical quality control system in a core laboratory.
abstract: BACKGROUND
  The aim of the clinical laboratory is to provide useful information for screening, diagnosis and monitoring of disease. The laboratory should ensure the quality of extra-analytical and analytical process, based on set criteria. To do this, it develops and implements a system of internal quality control, designed to detect errors, and compare its data with other laboratories, through external quality control. In this way it has a tool to detect the fulfillment of the objectives set, and in case of errors, allowing corrective actions to be made, and ensure the reliability of the results.
  
  
  OBJECTIVE
  This article sets out to describe the design and implementation of an internal quality control protocol, as well as its periodical assessment intervals (6 months) to determine compliance with pre-determined specifications (Stockholm Consensus(1)).
  
  
  METHODS
  A total of 40 biochemical and 15 immunochemical methods were evaluated using three different control materials. Next, a standard operation procedure was planned to develop a system of internal quality control that included calculating the error of the analytical process, setting quality specifications, and verifying compliance.
  
  
  RESULTS
  The quality control data were then statistically depicted as means, standard deviations, and coefficients of variation, as well as systematic, random, and total errors. The quality specifications were then fixed and the operational rules to apply in the analytical process were calculated. Finally, our data were compared with those of other laboratories through an external quality assurance program.
  
  
  CONCLUSIONS
  The development of an analytical quality control system is a highly structured process. This should be designed to detect errors that compromise the stability of the analytical process. The laboratory should review its quality indicators, systematic, random and total error at regular intervals, in order to ensure that they are meeting pre-determined specifications, and if not, apply the appropriate corrective actions.
authors.affiliation: Department of Clinical Biochemistry, University Hospital of Salamanca, Salamanca, Spain. Electronic address: f.marg@hotmail.es.
authors.forename: F
authors.initials: F
authors.lastname: Marques-Garcia
authors.affiliation: Department of Clinical Biochemistry, University Hospital of Salamanca, Salamanca, Spain.
authors.forename: M F
authors.initials: MF
authors.lastname: Garcia-Codesal
authors.affiliation: Department of Clinical Biochemistry, University Hospital of Salamanca, Salamanca, Spain.
authors.forename: M R
authors.initials: MR
authors.lastname: Caro-Narros
authors.affiliation: Department of Clinical Biochemistry, University Hospital of Salamanca, Salamanca, Spain.
authors.forename: T
authors.initials: T
authors.lastname: Contreras-SanFeliciano
mesh_terms: D002623:Chemistry Techniques, Analytical / Q000592:standards* / Q000706:statistics & numerical data; D064790:Clinical Laboratory Services; D019983:Guideline Adherence; D006801:Humans; D007120:Immunochemistry / Q000592:standards* / Q000706:statistics & numerical data; D007753:Laboratories / Q000592:standards*; D011785:Quality Assurance, Health Care / Q000458:organization & administration*; D011786:Quality Control; D015203:Reproducibility of Results
keywords: Analytical quality; Calidad analítica; Control system specifications; Operating rules; Regla operativa; Sistema de control especificaciones