Yes you can be unlucky with anything, but doing everything you can to ensure a healthy dog should be the top priority.
My girl has had blood work every year just as routine after my firsts problems. She has no symptoms, we just caught it on the yearly two years ago she slightly elevated, last year she was more elevated.
We first started just Nutramax denamarin, three months later it made no difference to her readings.
We switched her to Dr Dobs detox diet and Nutramax denamarin, went back after three months and her levels went up!
So now we have her on regular food, denamarin in the morning, milk thistle in the afternoon and twice daily 1000mg of fish oil.
Due to go back in February and see if that works. If not we will probably have to ultrasound. All her other blood work is normal so that is a good thing.