Cystic Fibrosis European Network

What is EQA?

Definition of EQA

EQA is defined by the World Health Organization as ‘a system of objectively checking laboratory results by means of an external agency. The checking is necessarily retrospective, and the comparison of a given laboratory’s performance on a certain day with that of other laboratories cannot be notified to the laboratory until some later. The main objective of EQA is not to bring about day-to-day consistency, but to establish interlaboratory compatibility’.

Main principles of an EQA scheme

  • A large number of laboratories are provided with the same material and they are required to return results to a coordinating centre.
  • There must be no difference in the treatment of an EQA sample and a patient sample: routine procedure and personnel who routinely perform the test.
  • The EQA results are compared to determine the accuracy of the individual laboratory.
  • EQA provides continuous education and training for laboratories, and should not be punitive.
  • EQA participation is a vital tool in a quality management system, especially for laboratories that are accredited or that plan to seek accreditation.
  • It is essential to follow-up EQA results and to discuss the reports in regular laboratory meetings; not only the negative remarks but positive results as well.
  • If fitting, the laboratory can report back to the EQA provider.

What does ISO 15189 require with respect to EQA?

  • Accredited laboratories are required to participate in interlaboratory comparisons such as those organized by EQA schemes.
  • EQA should, as far as possible, cover the entire range of tests, and the entire examination process, from sample reception, preparation and analysis to interpretation and reporting.
  • Whenever a formal interlaboratory comparison programme is not available, the laboratory shall develop a mechanism for determining the acceptability of procedures not otherwise evaluated; examples include reference materials or interlaboratory exchange. Interlaboratory comparisons should cover the scope of services offered and there should be a formal mechanism of review and comparison of results.


  • The laboratory is able to compare performance among other laboratories.
  • The laboratory is able to identify training needs or problems in laboratory practice.
  • The laboratory is able to show its customers the efforts made towards continuous improvement and quality assurance.

Type of errors identified by EQA

  • genotyping error
  • error in risk calculation
  • insufficient, poor or incorrect interpretation
  • clerical error
  • error in the nomenclature used
  • poor reporting format
  • transcription error
  • sample contamination
  • systematic problem associated with a specific method or kit


  • External quality assessment of health laboratories: WHO on Cystic FibrosisExit this website
  • Laboratory quality management system training toolkit: this website
  • CLSI: Using proficiency testing to improve the clinical laboratory; approved guideline, GP27A2, 2007
  • CLSI: Assessment of laboratory tests when proficiency testing is not available; approved guideline, GP29A2E, 2008
  • Approaches to quality management and accreditation in a genetic testing laboratoryExit this website
    Berwouts S et al., European Journal of Human Genetics, 2010, 18, S1-S19
  • An international external quality assessment for molecular diagnosis of hereditary recurrent fevers: a 3-year scheme demonstrates the need for improvement.  
    Touitou I et al., European Journal of Human Genetics, 2008, 16: 913–920
  • Experience and outcome of 3 years of a European EQA scheme for genetic testing of the spinocerebellar ataxias
    Seneca S et al., European Journal of Human Genetics, 2009, 17: 890–896
  • An Internet-based external quality assessment in cytogenetics that audits a laboratory’s analytical and interpretative performance
    Hastings RJ et al., European Journal of Human Genetics, 2008, 16: 1217–1224
  • External quality assessment for mutation detection in the BRCA1 and BRCA2 genes: EMQN's experience of 3 years.
    Mueller CR et al., Annals of Oncology, 2004; 15 Suppl 1:I14-I17
  • Quality of analytical performance in inherited metabolic disorders: the role of ERNDIM
    Fowler B et al., J Inherit Metab Dis, 2008, 31: 680–689

Last changed: 2019-10-29

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