Paternity Test

What is paternity testing?

It is a test that consists of determining the genetic map of the subjects submitted to the study. That is to say, its objective is to determine the filial relationship between two or more persons.

What does it consist of?

To perform this test the following samples are needed:

  • Hair with bulb.
  • Blood.
  • Cells from the buccal cheek.
  • Objects or tissues of the subject. Among the most common is a toothbrush or hairbrush.

Other centers may ask for a wider variety of samples, such as urine, fingernails, semen or chewing gum.

It is worth remembering that it is a simple test in which the cells of the child and the alleged father are studied. Once obtained, the corresponding analysis will be in charge of comparing the genetic map of both members to know the biological filiation.

Why is it performed?

There are several reasons why a paternity test is used. There are private paternity tests, legally valid paternity tests and prenatal paternity tests.

  • Private paternity testing. The results are merely informative for the persons tested and have no legal validity.
  • Paternity tests with legal validity. In this case, the samples can only be taken by legal professionals, who will keep the samples in order to guarantee their authenticity and integrity.
  • Prenatal paternity test. It is used when it is desired to know the paternity of a baby during pregnancy. For this purpose, amniotic fluid is obtained from the mother, which will provide the genetic information of the fetus. The DNA test will be performed from the eighth week of pregnancy.
See also  Cytology


No specific preparation is required.


The test results are obtained after two to three weeks and are 99.99% reliable.

To interpret the results correctly, it is important to know that the DNA test result will show each of the 21 loci used. Each person has two copies of a chromosome, one inherited from the mother and one from the father. For each locus two numbers are identified.

So, let’s take an example. For locus 5 the subject has two alleles labeled 15 and 17. This will mean that if the mother has those two alleles labeled 15 and 19, the child will have inherited from the mother 15 and 17 from the father. To confirm the paternity of the presumed father, he must have this allele.

Finally, it should be remembered that if the subject has received blood or bone marrow transfusions in the previous 6 months before undergoing the test, the results may be confusing.