A sibling test can determine whether or not two alleged siblings share the same father. There are two types of sibling tests:

Full siblingship test
This test is performed when two siblings know they have the same biological mother and would like to know if they also have the same biological father.

Half siblingship test
This test is performed when two alleged siblings do not have the same biological mother and would like to know if they have the same biological father.

Siblingship tests should include the two possible siblings and all available known parents. If available, the children’s mother or mothers are strongly encouraged to participate. The probability of obtaining more conclusive results is increased when known parents participate in the test. No more than two alleged siblings can be tested at the same time. If the mother or mothers are unavailable for testing a siblingship test may still be performed.

Siblingship test results are not as definitive as those of other paternity/maternity tests. The analysis of Sibling testing will produce a likelihood index or kinship index. There are two possible outcomes. A likelihood ratio of less than one suggests that the individuals are not related. A likelihood ratio greater than one suggests that they are related.

The turnaround time for this test is 3-5 working days. This test can be used for personal or legal purposes.

Alternatively a Y STR test can be performed if the siblings are male.