Reliability DNA tests

The results of our DNA tests are reliable. The tests meet both national and international quality standards.

The highest kinship probability value

The DNA tests in our laboratory will be performed with at least 15 different DNA polymorphisms for paternity, maternity, parenthood, family relation, and twin DNA tests. If there is no biological relationship, this result is based on at least three mismatched DNA polymorphisms. If there is a biological relationship, our tests will achieve a probability in the highest category for paternity, maternity, parenthood, twin DNA tests. This means the relationship is 'virtually proven'. 


If there is a biological relationship, the relationship index (I) and the probability of a biological relationship (W-value) are calculated using a statistical method.

For example:

For the paternity index we use the formula: I = X/Y, where X is the probability for the participating man to pass the allele to the child and Y indicates the probability for a random man to possess this allele. This formula is applicable to paternity, maternity, parenthood, family reconstruction and twin DNA tests.

W indicates the probability of paternity of the participating man. The W-value is expressed in several categories:

These categories are applicable to all our kinship DNA tests. 

Certified and accredited DNA tests

The DNA tests are performed in accordance with the DNA Research Decree 2008 (Staatsblad van het Koninkrijk der Nederlanden 2008, 20414, pdf, in Dutch). The DNA Paternity Testing department has been accredited by the Dutch Council of Accreditation (RvA), in accordance with the ISO 15189:2012 guidelines and the recommendations of the International Society of Forensic Genetics (ISFG) 2002-2007, accreditation number M005 (pdf).


Morling N et al. Paternity Testing Commission of the International Society of Forensic Genetics: recommendations on genetic investigations in paternity cases. Forensic Sci Int 2002; 129:148-157.

Gjertson DW et al. ISFG: Recommendations on biostatistics in paternity testing. Forensic Sci Int Genetics 2007; 1(3):223-231.

Last edited on: 28 May 2015