By the way, if the test was accurate that would mean that one of the grandparents or great parents was part westie the rest would be yorkie. But personally from what I have learned I think the test is flawed.
You shouldn't base if your dog is purebred or not on the test results you received. If you contact the company that did the testing they will confirm that it was not intended to prove if a dog is purebred. Ask the test company for clarification on the results and you will see what I mean.