Most illnesses will not affect your DNA and therefore will not affect your ability to test. However, if you have or have recently had an illness that has required antibiotics such as strep throat (Group A Streptococcus), you should wait until you are fully recovered before testing. Doing so will ensure that your samples contain your DNA and not that of the bacteria that caused the illness.
Medical situations that would be of concern would be: known genetic disorders, bone marrow transplants, and/or facial reconstruction with donor skin grafts in the mouth. In any of these cases, please contact us and discuss the specifics of your situation to determine if we can get a usable sample.