Sibling DNA Testing


If you have always wanted to take a sibling DNA test but have never known where to begin, then we are here to help!

Sibling DNA Testing provides the probability of genetic relationships between two people, specifically when no other relatives are available for testing. Sibling DNA testing has two categories; full-siblingship study and half-siblingship study.

Using targeted sequencing DNA Bioservices can determine genetic relationships between people.

Full-siblingship study

The full-siblingship test uses DNA samples to determine If you and your sibling share the same biological parent and/or parents. Please note:

  • The routine turnaround time for test results is 5-10 business days from receipt of specimen samples.
  • If a common parent of the donors is available for testing, they should be included in the analysis as this dramatically improves the accuracy of the test. Please be aware that in a small percentage of cases, the DNA evidence provided to the laboratory may result in an inconclusive report.
  • Conclusions are a "likelihood" routinely reported above 80% for inclusions or below 10% for exclusions.
  • We can perform a Full-siblingship analysis on a minimum of two alleged siblings.

How this test can help you!

There are several reasons why people choose to take sibling DNA tests. As this test determines genetic relationships between people, it can be vital in rebuilding a family relationship by genetically linking you to your siblings. Check out this case study to see an example of why someone would be encouraged to take a test:

Father is missing, and two individuals know that they share the same mother but are not sure if they have the same biological father. This test would determine if they have both the same mother and father.

Half-Siblingship Study

A half-sibling DNA test is for clients who want to determine if they have one parent in common. Please note:

  • Routine turnaround time is 5-10 days from receipt of specimen samples
  • No additional charge for one or both parents involvement
  • Conclusions are a "likelihood" routinely reported above 80% for inclusions or below 10% for exclusions.
  • We can perform Half Sibling test analysis on a minimum of two alleged siblings

To complete half-sibling DNA testing, follow the buy now link or contact our team over the phone via 1300 768 428.

How to complete the test

It's a really simple process that will bring you great results!

Order a test kit online and receive it straight to your door. Take swab samples and send the DNA kit straight back to DNA bioservices.

We will test the mouth swab and then provide the results in the form of a report.

How to read a sibling DNA test

Once your extended relationship testing is complete, you will receive a report that lists the number of genetic markers (loci) that were tested (a genetic marker is a DNA sequence that they need to identify people). You will also receive an explanation of the results.

Here is some clarification on potential terms that are within the report. First is the combined relationship index, where the relationship could be sibling, uncle, cousin, or grandparent. It's a measure of likelihood suggesting that an individual whose relationship is unknown is more or less likely to be the biological relative of another individual than another random untested unrelated individual. Here is an example:

Suppose a combined full-sibling index of 200 is determined. In that case, this indicates that John Doe is 200 times more likely to be the biological full-sibling of Jim Doe than another random individual.

The second term that you will receive is the relationship probability. In the case of siblings, this will be the result known as the Probability of Siblingship. Probabilities that are greater than 99% are strongly indicative of a true biological relationship. However, lower percentages may also indicate that a relationship exists and may support the available conventional genealogical records.

Likelihood indices and Probabilities of Relationships will improve by the addition of more loci (determined by the laboratory), provision of known ethnicities (can be determined by the client), or the addition of more known relatives (determined by the client through consultation with the laboratory).

Interpreting the figures

Generally, values greater than 100 support a true relationship; however, values even as low as two may still give evidence that a relationship exists. These values can change greatly by the addition of other known biological relatives relevant to the case.

For any further queries about your testing results, get in contact with DNA Bioservices.

Legal Application form

You can order this test as a non-legal or legal DNA test. Please call us on 1300 768 420 to discuss your options to qualify if this test is suitable for the donor's needs.

What's next?

DNA bioservices offer a range of other test types. Some of the key areas include:

  • Grandparentage test
  • Prenatal paternity test (including non-invasive prenatal tests)
  • Y Chromosome test
  • Ancestry tests
  • Wellbeing tests
  • And more!

Explore our website to learn about our range of tests.