Siblingship Test
A siblingship (or sibship) test determines if two or more individuals are biological siblings. Individuals are tested by collecting, analyzing,
and comparing DNA samples to see if they are biologically related, much like the procedure for paternity testing.
When is siblingship testing used?
Siblingship tests have many uses. For families, they can provide information about siblings and parents. Siblingship tests can determine
if two or more individuals are siblings, and if they are full- or half-siblings. If a parent is missing, siblingship tests can provide
useful information about the missing parent's paternity or maternity.
Siblingship tests also provide useful biological information for legal cases. They can be used in cases dealing with Social Security benefits,
inheritance claims, immigration, child support, and
adoption identification and reunification.
Who is typically involved?
To take a siblingship test, two alleged siblings must be involved. Any known
parent of the two alleged siblings is often included in the test as well, as his or her genetic information is helpful in verifying the possible relationship between
the siblings.
How are the samples collected?
Samples can be collected in several ways. Buccal swabbing is the most common collection technique,
though several alternatives to it exist. Be sure to speak with the DNA testing company you choose to pick the best collection option for your
situation.
It is important that you speak with the company through which you plan to take your siblingship test before you make a decision on which type of samples
to use.
You can learn more about DNA sample collection procedures by visiting the Sample Collection page.
How long can the results take?
You can expect siblingship test results to take anywhere from 5 to 20 business days. The turnaround time for the test results depends on the
difficulty of the test. Siblingship tests take longer if no parent is tested or if the relationship being tested is that of half-siblingship. Also,
the results can be delayed depending on the DNA sample type and the number of siblings to be tested.
For a typical siblingship test involving two potential siblings, a mother, and buccal swab samples, results are usually ready in about 14 business days.
How conclusive are the results?
The results for siblingship tests are generally not as definitive as the results for paternity or maternity tests. However, results for a
full-siblingship test with the involvement of one or both biological parents will produce a high probability of full-siblingship, often above 90%.
Siblings are tested two at a time, and the results of their tests are typically given as a Combined Siblingship Index (much like the
Combined Paternity Index). This index
number is a statistical value that gives the genetic odds that the two siblings are biologically related.
You may receive results that are given in probability of full-siblingship or probability of half-siblingship. Unlike paternity and maternity
tests, this probability will not provide overwhelming certainty of a biological relationship. Rather, this probability will show whether the siblings
are more or less related.
Most states have laws about what probabilities are acceptable in legal cases, but in general, if you receive a
probability of siblingship below 90%, the
results will be considered inconclusive and inadmissible in court.
What is the typical price range for siblingship testing?
The price of a siblingship test can range from $500 to more than $1,000. The total cost depends on the number of people involved
in the test and the use of the test results.
In general, most DNA testing companies have a standard price for a siblingship test that includes two siblings and a parent. For each additional
sibling to be tested, the company will increase the price. Also, due to the difficulty of testing, the price will increase if no parent is tested.
The price will also vary based on the use of the test results.
If you are taking a siblingship test for peace of mind or another non-legal purpose, you can take an in-home test that can cost from
$400 to $650 for full-siblings or $500 to $750 for half-siblings, testing two siblings and a parent. For each additional sibling, the cost may increase by $100 or
more.
If you need the results of the siblingship test for legal reasons — such as for child support,
immigration, or adoption cases — you should take a
chain of custody siblingship test. The cost for a chain of custody test can range from
$600 to $800 for full-siblings or $850 to $1,000 for half-siblings.
As with the in-home test, the price for a
chain of custody test may
increase if no parent is involved or if you want to test more than two siblings. The price increase for each additional sibling is typically
around $200.
You can learn more about the reasons behind the wide range of testing costs by visiting the Price Differences page.
What else should you know about siblingship testing?
You need to consider the future use of your siblingship test results before you choose your DNA testing service. Most cases involving siblingship
tests require chain of custody testing.
You can learn more by visiting the Do you need a chain of custody test? page.
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