In order to use DNA tests in genealogy, you need to know every segment on every chromosome that matches. Matching is not a go/nogo proposition. There are degrees of matching that depend on the biological relationship. Ex: Parent/children average 3,700 cM (centiMorgans), siblings are 2,600 cM, first cousins 900 cM etc.
See: https://whoareyoumadeof.com/blog/need-a-dna-centimorgan-char...