It wasn't a breathalyzer, it was a sobriety test. The officer asks you to perform simple tasks; contrary to popular belief, they're not just looking for super obvious movements like stumbling around while walking on a straight line, they're looking for specific signs that show up in drunk people, like horizontal eye movements or difficulty balancing. The problem with these tests is that while most intoxicated people will show these signs, plenty of sober people will, too. It's incredibly subjective. The error rate is staggeringly high, because the test is based on unreliable statistics and poor training of the officers.

So the officer, using subjective judgment, gave OP a DUI. That means the officer is the one that is responsible for the blood test being performed. The officer is the reason OP's car was impounded, and the officer is the reason OP had to go ro hearings. It was all based on a mostly subjective assessment by the officer.