All saliva samples are inspected and must pass certain tests to continue being processed. If a sample doesn’t pass quality checks at any point, you may be offered a replacement kit to submit a new sample. For tips on providing a saliva sample, read collecting a saliva sample.
Common reasons a sample may fail
- Cap problems that result in loss of saliva during shipping
(for example, if the cap isn’t installed correctly or tightened enough) - Saliva and stabilizing fluid not fully mixed
- Too much or too little saliva in the tube
- Contamination (anything other than human saliva and stabilizing fluid in the collection tube), including:
- bacteria
- food or drink particles
- toothpaste or denture cream
- chewing tobacco
- hair or fingernail clippings
- swabs or other materials
- DNA from more than one person, including:
- multiple people spitting into the same tube
- recipients of bone marrow or stem cell transplants from another person
- Certain medical treatments that can temporarily affect DNA quality, like chemotherapy
- Sub-optimal or highly degraded DNA
In some cases, a sample may fail quality checks during the testing stage at the laboratory for reasons unrelated to sample collection.
Frequently asked questions
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Why didn’t my DNA sample pass quality checks?
All saliva samples go through multiple quality checks before and during testing. A sample may fail if it doesn’t meet laboratory standards for DNA quality, quantity, or consistency, and we’re not always able to identify one specific reason.
A single failed sample doesn’t mean anything is wrong with your DNA. DNA sample quality can vary for many reasons, including factors outside of your control. That’s why, if your sample fails, we may offer a replacement kit so you can submit a new sample and try again.
Could my sample fail if the cap wasn’t tight or the blue fluid didn’t release or mix?
Yes. If the cap isn’t screwed on tightly or the blue stabilizing fluid doesn’t release or fully mix with the saliva, the DNA may not be preserved properly or saliva may leak during shipping. This can cause a sample to fail quality checks.
Following the collection steps, especially tightening the cap and shaking the tube to mix the saliva and stabilizing fluid, can help reduce the chance of a sample failing. If a sample doesn’t meet quality standards, you may be offered a replacement kit to try again.
Can contamination cause a sample to fail?
Yes. Samples that contain anything other than saliva and stabilizing fluid may cause a sample to fail quality checks. Contamination can include food, toothpaste, denture cream, chewing tobacco, hair, fingernails, or other materials.
Can a DNA sample fail even if I follow all of the instructions?
Yes. In some cases, a sample may fail even when all instructions were followed. DNA quality can be affected by factors outside of your control, including natural variation in saliva, such as saliva that’s too thick or too thin, sub-optimal or degraded DNA, or laboratory testing limitations.
Can medical treatments affect DNA testing?
Yes. Some medical treatments can affect DNA testing. For example:
- Chemotherapy can affect the amount or quality of DNA in saliva, which may increase the chance that a sample doesn’t meet quality standards during testing. If that happens, you may be offered a replacement kit.
- Recipients of bone marrow or stem cell transplants from another person may have mixed DNA in their saliva, which can result in inconclusive results or results that reflect the donor’s DNA instead of their own. Therefore we ask that you not submit a sample. Consider giving the kit to a family member, or contact us so we can review your options and discuss next steps.
Can an older kit and sample affect results?
We only provide AncestryDNA results when a sample meets quality standards. Older kits or samples may affect whether a sample meets quality standards for processing, but they won’t affect the accuracy of results we deliver if the sample can be processed.
Even if some time has passed since you collected your sample, we recommend sending it back so we can try processing it. If your sample doesn’t meet quality standards, you may be offered a replacement kit to send a new sample.
Why can’t non-saliva samples be processed?
The AncestryDNA test is designed to analyze DNA from human saliva collected using an AncestryDNA kit and its supplies. Because of this, if the collection tube contains anything other than saliva and stabilizing fluid, such as blood, hair, swabs, urine, or other materials, the sample won’t meet quality standards and can’t be processed.
If this happens, you may be offered a replacement kit.
What if I don’t want to submit another sample after one fails?
If your sample failed and you’d rather not submit another one, contact us so we can review your options and discuss next steps.
