DNA Sibling Test

The sibling test offers an estimation of the probability that two individuals are either full siblings, half siblings, or unrelated.


DNA Tests
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* All kits are dispatched within 24 hours. Price includes all laboratory fees and results documents.

Test Description

We use a non-invasive, pain-free DNA collection method for paternity testing and DNA analysis. Using the latest technology, a buccal cell sample taken from the inside of the mouth is now the newest and most recommended method for sample collection. A buccal cell sample can be collected quickly, painlessly and discreetly using the home collection kit.

How to Read a DNA Test Report

Limitations of DNA Sibling Testing and Indications for Use

The sibling test is not as powerful as the paternity test. The paternity test will always give an absolutely conclusive result regarding paternity. Whenever the alleged father is available for testing, the paternity test is always the recommended test as it is the most powerful and conclusive test. However, in cases where the alleged father is not available for testing and there is no other option but to test the siblings, the DNA Sibling test will provide you with the likelihood that two individuals are full siblings or half siblings or not related at all.

Understanding the DNA Sibling Test Report

The DNA sibling test report will provide you with a full sibling index and a half sibling index. The full and half sibling indexes will tell you whether the siblings are most likely to be full siblings (two parents in common), or half siblings (only one parent in common) or not related at all (no parents in common).

100% Confidentiality

As our client, your privacy is extremely important to us, and we hold all information provided us in strict confidentiality. We will never sell, resell or make available your personal, or financial information to other companies or organizations. You will only be contacted using the method you choose, to confirm your order or to discuss your case. All communication is in the strictest confidence, and for that reason, we require you to create a password that will restrict access to your case. In addition, our privacy policies that have been established in our laboratory and offices safeguard the security of your case.

Highest Standards

Our testing laboratory is AABB and ISO17025 accredited for chain-of-custody legal testing. These accreditations provide a full guarantee of accurate, straightforward, and reliable results.


Every person has two copies of each gene. One copy comes from the mother and the other copy comes from the father. Thus, one half of the genetic material in our body is inherited directly from each of our two parents. When a DNA sibling test is performed, the DNA laboratory examines the DNA of each sibling and then compares them to generate a full sibling index and a half sibling index. Individuals who are full siblings are expected to have a full sbiling index that is greater than 1.0 and the valueof the full sibling index will be higher than the value of the half sibling index. Individuals who are half siblings are expected to have a half sibling index that is greater than 1.0 and the half sibling index will be greater than the full sibling index. Individuals who are not related are expected to have a full sibling index that is less than 1.0 and a half sibling index that is less than 1.0.

The sibling test is a statistical analysis based on the pattern of expression of genetic material in the siblings compared. The sibling test is not as powerful as the paternity test and should only be considered if the alleged father is not available for testing. If the siblings are known to share the same mother and it is only the father to is in question, then adding the mother to the DNA sibling test can help to increase the discrimination power of the test. In studies of large siblings groups, the analysis of multiple siblings in the group can help to generate a better overall picture of the inter-relationships between the siblings.

A results interpretation sheet is provided with your results report.

Both the Legal and Private tests are equally accurate and both will provide absolutely conclusive results. If you choose the private test, a home kit will be sent to you so that you can collect the samples discreetly in private. If you choose the Legal Test, the collection must be done by an unbiased individual (doctor, lawyer, notary, etc.) and all individuals attending the collection appointment must bring a passport photo, picture identification, and they will be fingerprinted during the sample collection appointment. If you do not need to use the results in court, then the private option will provide the same conclusive results as the legal test and can be done discreetly.

If the parties to be tested living different cities or different countries, the kit can be split and sent to each individual separately. The kits are individually barcode labelled so once the samples arrive back at the laboratory, they will be sted together. To order a split kit, please write the following into the comments box of the online order form when you place the order “Please split kit. Please send one portion of the kit to: (person’s name and address), and please send the other portion of the kit to: (other person’s name and address).”

CODIS stands for Combined DNA Index System. The CODIS loci are the loci which are approved by the FBI and other recognized standardization bodies worldwide for databasing and genetic profiling. At International Paternity Labs, 13 out of the 16 loci which we test are CODIS loci. As such, the profile obtained from each test far exceeds the current recognized standards.

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