Sibling DNA Test

For a sibling DNA test, cheek swabs are used to collect DNA samples from each sibling and the biological mother, if available. 

Once these samples arrive at the laboratory, our in-house geneticists analyse and compare the DNA samples to determine the genetic profile of the possible siblings and calculate a sibling DNA index or likelihood ratio.

• A likelihood of greater than 10 supports that the tested individuals are either full or half siblings
• A likelihood of less than 0.1 is not supportive, meaning the individuals are unlikely to be related
• A likelihood which falls between 0.1 and 10 is considered inconclusive, which means a relationship cannot be determined based on the statistical probability obtained from the analysis

AlphaBiolabs is the UK’s No.1 DNA testing laboratory, with over 20 years of experience providing at-home DNA testing for peace of mind.

We pioneered the fastest DNA results worldwide, with next-day* results available as standard for our peace of mind DNA tests – an achievement that saw us awarded the Queen’s Award for Enterprise.

We even offer same-day results for +£70.*

Additionally:

• We analyse up to 45 DNA markers (loci) – twice as many as our competitors
• We’re UKAS ISO 17025-accredited (No. 2773), ensuring our processes meet the highest international standards for accuracy and reliability
• Our easy-to-use home test kit allows you to collect your own DNA samples quickly in the privacy of your own home
• All tests are performed at our UK laboratory, so your samples won’t be sent abroad
• We’re rated ‘Excellent’ on Trustpilot, based on reviews from real customers
• We prioritise your privacy and guarantee 100% confidentiality throughout the testing process. This includes sending your test kit in discreet, plain packaging, and delivering your password-protected results via secure email
• Accurate results, based on the samples we receive into our laboratory
• Only a simple cheek swab required from each sibling and the biological mother (if possible)

*Business days from when your samples arrive at our laboratory, before 10am.

Our standard sibling test is already industry-leading, as it analyses 25 DNA markers (the industry standard only analyses 16-21 markers).

What makes AlphaBiolabs unique is that we can also analyse up to 45 DNA markers. This allows more genetic material to be analysed, which strengthens the result and provides additional reassurance.

This is ideal for customers who want the most powerful DNA test available.

Our Sibling DNA test results are accurate and reliable based on the samples we receive at our laboratory.

We are also accredited to the international quality standard ISO 17025 for our DNA testing.

The difference between full and half-sibling DNA stems from how many biological parents they have in common.

Full siblings who have the same biological mother and father are known as first-degree relatives and share approximately 50% of their DNA.

Half siblings who have one biological parent in common – their mother or father – are known as second-degree relatives and share approximately 25% of their DNA.

Yes, the Sibling DNA test can be used to determine whether individuals are half siblings.

Half siblings (e.g. half brothers / half sisters) share one biological parent – the mother or father – and will normally share more DNA than people who are not related.

This makes it possible to use sibling DNA testing to determine whether individuals are:

• more likely to share one common parent (i.e. they are half siblings, with one biological parent in common) or
• are more likely to be unrelated

A sibling DNA test requires cheek cell DNA to be collected from each sibling using cheek swabs.

We also ask that the biological mother’s DNA sample be provided where possible, for the most conclusive result. However, we can still perform the test without the mother’s sample.

Your DNA test kit will contain enough cheek swabs to collect DNA samples from two siblings and the biological mother (if available), along with full instructions on how to collect your cheek cell DNA samples and return them to our laboratory.

You can also choose to add a third sibling to the test for an additional £49, and more cheek swabs will be provided in the test kit.

For the most conclusive result, we do ask that the biological mother also provides a cheek swab sample, if possible.

However, this is not essential, and we can still perform a sibling DNA test without the mother’s sample. 

Your test kit will contain enough cheek swabs to collect DNA from two siblings and the biological mother (if available).

Yes, a sibling DNA test can be performed without a parent’s sample.

For the most conclusive result, we do ask that the biological mother also provides a cheek swab sample, if possible. However, this is not essential, and the test can still be performed without the mother’s sample.

Yes, you can choose to send a test kit to a second address, for an additional fee.

Simply choose this option when placing your order.

Once your DNA samples arrive at our laboratory, testing can begin.

You can choose to receive your results the next day* (included in the cost of your test), or the same day* for an additional £70.

Simply choose your preferred option when placing your order.

*Business days from when your samples arrive at the laboratory, before 10am

You can order an AlphaBiolabs Sibling DNA test for £149. The cost of the test includes all fees for laboratory testing and analysis. 

This includes DNA testing for two siblings, and Royal Mail First Class shipping for your test kit. 

You can choose to add a third sibling to the test for an additional £49.

We also provide additional shipping options for your test kit, including Next Business Day Courier (+£9.95).

You can order your Sibling DNA test here for just £149.

Your test kit will be shipped out to you immediately in discreet, plain packaging.

Need advice on whether this test is right for you? Call our friendly and knowledgeable Customer Services team on 0333 600 1300 or email info@alphabiolabs.com.

Our Sibling DNA testing kit includes full instructions on how to collect your cheek swab samples, DNA swab packages, swab envelopes, individual DNA test sample envelopes, and a self-addressed envelope to send your test samples back to us.

Your test kit will be sent out in discreet, plain packaging for full confidentiality.