Proficiency testing

Intercomparison Exercises program 'Analysis of DNA polymorphisms in bloodstains and other biological samples'

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Since 1992, the Spanish and Portuguese Speaking Working Group of the International Society for Forensic Genetics (GHEP-ISFG, formerly called GEP-ISFG) has been organizing an annual Intercomparison Exercise in order to provide laboratories investigating DNA polymorphisms in forensic biological samples, a proficiency test to assess the quality of the results, assist in the unification of criteria and the implementation of new techniques, and serve as a proof of competence of the laboratory performing the tests. This exercise is coordinated by staff from the Quality Assurance Service at the Madrid Department of the National Institute of Toxicology and Forensic Sciences (Ministry of Justice, Spain).

The results of this proficiency exercise are presented and discussed at the annual meeting (Meeting on Forensic Genetics of the GHEP–ISFG), which represents a forum for discussion among participants where the difficulties of the analysis of DNA polymorphisms are put forward together with the need, from a legal and practical point of view, to carry out the analysis with the required assurance.

More than 20 editions have been held up to now and the number of participating laboratories has increased each year, from 10 laboratories in the first exercise to over 120 participants in recent years. Most of the participating laboratories are from Spain, Portugal, and several Latin American countries, and to a lesser extent laboratories located in other European countries (France, Italy and others) take part in the Exercise. In general, they are public institutions although the number of private laboratories has notably increased in the last years. 

The intercomparison program entails practical exercises in which participating laboratories are asked to analyze different samples: bloodstains, saliva and/or other biological fluids and hair sample, simulating real casework, and also a theoretical exercise of applied statistics which involves the assessment of mock cases by means of statistical calculations. Applicants can select two different modules: Kinship and Forensics and choose between two levels: Basic or Advanced level. On December 5, 2014, the Basic Level of the Exercise was accredited by ENAC (National Accreditation Entity in Spain) under the standard ISO/IEC 17043: 2010.

The practical studies involve carrying out genetic analysis by different PCR systems: autosomal STR markers, Y and X chromosome STR markers, and mitochondrial DNA polymorphisms. Body fluid identification is also requested. Recently analysis of non human samples has been incorporated. Obtained results are published in this web anually, after the celebration of the Meeting, so that they are available to all the participants and GHEP-ISFG members.

Any laboratory interested can take part in the exercise. Each laboratory is assigned a code to ensure anonymity in the results generated. For each module and level a certificate of participation and results obtained by the laboratory is issued.

The open enrollment period is the last quarter of each year and it is announced in this web together with all the relevant information concerning the Exercise. Registration should be done online on this web. The samples are shipped during February of the following year.

The effort spent to develop this exercise is compensated by the significant acceptance shown, together with the good results that are being obtained. The Exercise together with other activities promoted by the Group, greatly help to enhance and unify the quality of the analyses performed in the forensic genetics laboratories and to encourage the standardization of techniques and criteria.


Rules of paticipation