People put a lot of trust in chemical testing, even though no testing system is absolutely infallible. There is often an assumption that those accused of crimes are likely guilty if the state has some kind of physical or chemical evidence.
Some people accused of driving under the influence (DUI) offenses in Pennsylvania plead guilty right away because they assume that if they failed the breath test, it will be impossible to defend themselves against their criminal charges.
While it is certainly true that the prosecution will likely use a failed breast test as a major piece of supporting evidence in the case against you, you are not guaranteed to end up convicted of a DUI just because you failed a breath test.
There could have been a false positive
There are a surprisingly wide array of reasons that a sober person could fail a breath test. False positive test results are a well-known issue. Both those following keto diets and people with uncontrolled diabetes could fail a breath test because of their blood sugar situation.
Other people could fail a breath test because they recently used an asthma inhaler or mouthwash. There are even some rare medical conditions that can make it look like someone consumed alcohol when they did not, like auto-brewery syndrome.
Finally, there could be false positives on the test because of issues with the testing unit itself. Police departments should routinely calibrate their devices and engage in proper maintenance, which includes software updates. Issues with the testing unit itself might be to blame for a false positive.
People can and do challenge breath tests
Depending on the circumstances that led to your arrest and the reason you think you can challenge the breath test, you could potentially ask the courts to exclude your chemical test results from your criminal proceedings.
In some cases, that may be enough to get the charges against you dismissed. Other times, it will be a huge help in creating a reasonable doubt about your actual chemical state at the time of the traffic stop. Realizing that you can fight back against DUI charges might inspire you to mount a defense in criminal court when accused of drunk driving.