Waiting for your results can seem like the most nerve-racking part of taking a paternity DNA test. But once they arrive, understanding what they mean – and how accurate they are – becomes just as important. If you’re considering an at home test, you might be asking “how accurate are paternity tests?” and “can you trust the results?” and wondering how home tests compare to those carried out in a clinic or by sample collectors. So, we’ve broken down everything you need to know about the accuracy of paternity tests and what can affect your results…
What is a paternity test?
A paternity test compares the DNA of a child and a potential father to determine if they share a biological relationship. A child inherits 50% of their DNA from each parent, so by analysing 24 genetic markers, we can confirm or exclude paternity with a high degree of certainty (> 99.99%).
Can paternity tests be wrong?
When conducted by an accredited laboratory and with proper sample collection, DNA paternity tests are extremely reliable.
Rather than producing an incorrect result, any uncertainty is handled through strict reporting standards. If there is not enough statistical evidence to confirm or exclude a biological relationship, the result is reported as inconclusive rather than risking an inaccurate conclusion.
There are several factors that can affect whether a test produces a clear and conclusive result.
What affects DNA test accuracy?
There are several factors that can influence the likelihood of receiving a clear and conclusive result when testing a potential father and child:
- Sample collection: correct sample collection is essential. We provide two swabs per person, which should be rubbed on the inside of their cheek for 20-30 seconds, ensuring you collect cheek cells rather than just saliva. Poor collection can affect the quality of the DNA samples.
- Including the mother: while not required, including the mother in the test can improve its chances of a conclusive result. By analysing her DNA, we can isolate the DNA that the child inherited from the father more precisely, allowing for a more accurate conclusion to be drawn. It also provides additional reassurance that the correct child has provided a sample.
- Related fathers: if two or more potential fathers are related (e.g. brothers), testing becomes more complex because they share more DNA. In these cases, we do require additional information regarding the specific biological relationship of the potential fathers as it will require specific statistical analysis. Please get in touch with us before booking to tell us how the potential fathers may be related.
- Laboratory standards: using an accredited laboratory like NorthGene™, which is UKAS accredited, ensures strict quality control and validated methods throughout the process, and reliable results.
What will the results say?
Results are highly accurate when paternity testing is performed correctly and presented in a clear, easy-to-understand format, supported by statistical analysis.
Your results will show one of two outcomes:
- Inclusion: the man is 99.99% likely to be the biological father of a child
- Exclusion: the man is not the biological father
Probability of paternity is calculated by carrying out statistical analysis of the DNA markers, taking into account how common specific genetic profiles are within the general population. This ensures that matches are due to a biological relationship rather than coincidence.
In rare cases – particularly in those where only one parent and a child are tested – the data may not be strong enough to produce a conclusive result. When this happens, our expert team may recommend:
- Including the mother
- Performing extended marker testing
Both options increase the strength of the analysis and improve the likelihood of a conclusive result.
Understanding inconclusive results
An inconclusive result means there is not enough statistical evidence to confirm or exclude a biological relationship between a potential father and child. This can happen because some genetic markers are shared across the wider population, even between unrelated individuals.
At NorthGene™, we analyse 24 genetic markets to significantly reduce the likelihood of inconclusive results. For paternity testing, results are only considered inconclusive if the probability falls between 0.02% and 99.98%. Outside of this range, results are reported as conclusive.
Note: Only 0.1% of the paternity test results we issue are inconclusive, and this can often be resolved by including the mother.
As a UKAS accredited and Ministry of Justice approved laboratory, we follow strict reporting standards and cannot speculate on results unless they meet legally defined thresholds.
Learn more about inconclusive results.
Common misconceptions about home paternity testing
| Myth | Reality |
| At home tests aren’t accurate | At home tests use the same laboratory methods as legal tests and are equally accurate when samples are collected correctly |
| You must include the mother | The mother’s DNA is helpful but not required for a conclusive result |
| Results can be 50/50 | Paternity tests do not produce estimates. Outcomes are either conclusive or inconclusive based on strict thresholds |
Accurate paternity test results with NorthGene™
For many families, a paternity test isn’t just about science – it’s about clarity, confidence and peace of mind. When carried out correctly, paternity testing is one of the most accurate forms of genetic testing available today. While waiting for answers can feel overwhelming, understanding how the process works – and the safeguards in place – can offer real reassurance.
At NorthGene™, we combine advanced DNA analysis with strict laboratory standards to ensure every result is as reliable and clear as possible. From carefully designed test kits to UKAS accredited processes within our North Wales laboratory, every step is focused on giving you answers you can trust.
To find out more about peace of mind paternity testing with NorthGene™ or to begin your journey with a simple at-home kit, explore our services today.




