Depending upon where the DNA test was done through, You can download the DNA results into a zip file on your computer. It can then be “uploaded” to several other DNA - Ancestry sites and will give more expansive interpolation.. GEDmatch is pretty cool. You can compare your DNA with a number of different research studies of different compiled groups.. DNA worked for me. I found a few half-siblings earlier this year.. https://www.yourdnaguide.com/upload-to-gedmatch/
Then there is the difference between dna and kinship. It is theoretically possible to get NO dna from one of your grandparents, even without any hanky panky, but you are still kin.
Chances of having little or none of a true relative’s dna increase the further back you go. This is because you don’t get All of Mom’s and Dad’s dna, but half of each.
This is also why siblings can differ so much.