1. Nails: If you want to use nails as a DNA sample, we recommend that you re-create another sample every month.
2. Saliva: It is useful for 3 days.
3. Buccal Skin Cells: After 4 or 5 days, the specimen need to be changed.
4. Blood: Blood could be good for about 5-6 days.
5. Hair with Follicles: Hair samples are good for about two days.
More information about DNA samples, please click this link: https://www.spooky2-mall.com/blog/what-you-should-know-about-dna-samples/