Sibling DNA Testing
This kind of testing is used to determine whether two test patients have either biological parent in common in the event that their alleged parents are not available for testing.
However, you should be aware that sibling DNA analysis is not as conclusive as paternity testing; the test results will only supply the statistical likelihood of whether two individuals are biological relatives based on their DNA samples.
According to statistical analysis, siblings who have the same two biological parents will have more DNA markers in common than half siblings, while half siblings are more likely to share a greater number of DNA markers than totally unrelated people.