Interpreting a DNA Relationship Test Result

How it works

Unlike a DNA paternity test, which will always provide a conclusive result, relationship tests are different as they involve the comparison of less direct relationships than those between parent and child.

When such a test is conducted, the laboratory will determine the genetic profile of the alleged relatives based on the type of genetic information exhibited by each person. The comparison of these profiles will generate a relationship index known as the Combined First Order Index that is then reported in your DNA test together with the Probability of Relationship.

The result of the Combined First Order Index can be used in the following manner to interpret the results:

If the number is less than 1, it is unlikely (<50%) that a biological relationship exists between the individuals tested. If the number listed is equal to 1, then a 50% probability exits that they are biologically related. As the number increases, so does the percentage probability of a relationship. When the number reaches 100, the tested relationship is highly probable, practically proven.

easyDNA will always aim to try and achieve a Probability of Relationship giving an inclusion of 99% or an exclusion of 0% – however this is not always possible and will depend on how unique is the DNA of the persons tested and who is actually tested. We normally take a range of 80%+ for an inclusion; a percentage below 20% can give an indication but is not enough to confirm or exclude a biological relationship between the parties tested. Further testing using other blood relatives is recommended in these cases.

Therefore, although the relationship test does not guarantee to always provide you with a conclusive answer, it may be able to provide you with an indication of whether you are more likely to be or not to be the true biological relative of the other tested individual.

easyDNA has a number of relationship DNA tests available. These tests can be done for any of the following reasons:

• Peace of mind
• Legal purposes
• Immigration

Relationship tests include various DNA tests usually carried out between siblings, DNA tests between grandparents and grandchildren and others.

The most important thing when seeking a relationship test is to have your objective clear and know exactly what you need to find out. This will help us guide you to select the most suited DNA test. For example, if you are both males wishing to know if you have the same father, we would suggest a Y chromosome test but if you are a male and a female wanting to confirm the same thing, we would suggest a full sibling test.

With our many years of experience and technical expertise, easyDNA can often recommend alternatives that may not even have occurred to you. To get more information about each of the relationship tests we offer Click here