Guidelines
Samples should be collected at least one hour after:
- Brushing teeth, using mouthwash - will cause not as many cheek cells to be collected on the swabs
- Drinking or eating anything except for water, especially hot food or beverages - food and sugary drinks could contaminate a sample and encourage bacterial or fungal growth or result in too much non-human DNA being present in the sample.
- Smoking, chewing tobacco, dipping tobacco or herbal dips of any kind - leaves residues and particulates that contaminate samples.
Furthermore, if the DNA donor wears dentures or partials, dentures should be removed and cleaned with plain water, and the mouth should be free of any denture adhesives, oral analgesics or clove oil. Denture adhesives destroy DNA in samples and make them unusable and analgesics may contaminate the sample.
Medical Concerns
Certain medications and procedures used to treat cancer have also been known to disrupt the structure of DNA and can also lead to sample failures.
In general, for patients undergoing chemotherapy or radiation in cycles, it’s best to wait until just before the next cycle to swab. If the radiation therapy is focused on the head or mouth, contact Customer Service with the specific details before swabbing. Radiation therapy in other areas of the body is not likely to affect the test.
If the tester has had stem cell therapy with stem cells other than his or her own, or has had a bone marrow transplant, it is likely that the sample will not accurately reflect the tester’s own genetic makeup.