February 25, 2007

Are paternity tests %100 accurate?

The accuracy of DNA paternity testing is a question that many people asks when looking into having a DNA test done. Although no test can ever be 100% accurate, the importance of this relies on how confident you can be on the result, or how likely is that the paternity test results will resolve your paternity doubts.

Two kinds of results are involved in a paternity test. The first is called exclusion, which means that the individual being tested is excluded from being the biological father of a child. The paternity test revealed that the DNA of the person was not similar enough to the DNA of the child to consider him as the father. Exclusion results are almost always conclusive. If a man is excluded from being the father, the only possible scientifically relevant explanation is that he is not.

Inclusion of paternity are a different thing. Probability and likelihood of being the father are always considered here. Although no test can achieve 100%, the DNA analysis are carried out in such a way that at least 99% probability is obtained, although some DNA labs achieve 99.99% certainty that a child is the father.

The accuracy of a DNA test depends on how many markers (or loci) are tested on the DNA of the alleged father and child. More markers or loci means more accuracy, and fewer chances for error.

The most accurate DNA tests employ at least 13 to 16 loci or markers. Tests that use less than 13 markers still provide reasonably high levels of confidence, but the difference in the price of the test does not justify choosing the cheaper, less accurate tests.

Although %100 accuracy is technically not possible, 99.99% is considered a perfectly conclusive result. This level of accuracy can be obtained through testing a larger number of genetic markers and good DNA testing labs usually test 16 of such genetic loci. Always look for accredited DNA labs to clear up your doubts confidently.

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