This morning my cat was retested and thyroid levels were very high

my cat was diagnosed with Hyperthyroidism last year and put on Tapazole '2x times a day' one-half a pill
This morning my cat was retested and thyroid levels were very high. But i think the test results may not be accurate

My Tapazole pills for my cat ran out 4 days before the test. The day before the test i found one pill and gave it to my cat. I am not sure the vet who did the test today was aware of this. i may be wrong but i thought i read somewhere the cat needs to be taking the Tapazole right up til the test otherwise the test results will be wrong. Any thoughts before i call the vet

You can't let your pills run out. Before mine do, I always get more. I give my kitty his pill the same time every day also.

That could be the reason his numbers are high.