About sibling DNA testing

A full siblings test is recommended when the individuals taking part in the test are male and female. This type of test establishes the amount of common DNA between the people tested. It is a test that relies on a statistical probability. Unlike a paternity test however, sibling testing does not need to provide genetic profiles that match at every genetic marker. A sibling test simply seeks to determine whether the individuals tested share one common parent, both common parents or have neither their mother or father in common. In a sibling ship test, we calculate a siblingship index. If the siblingship index is less than 1.00, this indicates non-relatedness. If the siblingship index is greater than 1.00, this indicates that the two tested individuals are more likely to be true full sibling or half siblings. The cost of the sibling DNA test is $349.

In cases where testing takes part solely between male individuals or female individuals we can recommend other types of sibling DNA tests.

We strongly suggest including the sample of a known mother to provide stronger results.

PLEASE NOTE: In the event of a possible pre-existing relationship the laboratory would NOT be able to run a sibling test if you believe your cousin could be your sibling. Please contact us to help you find the right test for you.

Important Notes

Note: We can only guarantee standard result turnaround time when testing takes place solely using oral swab samples. Using a discreet sample for your test may lead to an increase in turnaround time.

Test results are intended to provide a statistical likelihood that gives evidence to support the tested relationship in question. Providing additional parties to be tested (for example, a known parent’s sample) or performing direct relationship testing may provide additional evidence.

We strongly suggest including the sample of a known parent to provide stronger results.

In cases where siblings are male

If siblings are male and want to discover whether they share the same biological father, we suggest a type of sibling DNA test known as a Y chromosome test. This test is extremely accurate. If males tested wish to know whether they share the same father for example, a Y test would be ideal. If they have the same DNA profile, then they share the same paternal line. If two If females wish to establish whether they have a common paternal line they can ask a direct male blood relative to take a Y chromosome test on their behalf.

What is STR analysis?
Understanding your relationship test results

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