Breathalyzers can have false results, which is why you can question a result's legitimacy in court. There are dozens of reasons why a breath test could be inaccurate. One reason that you need to know about is if you have acetone in your breath. Acetone exists in most people's breath, but in some, it can be high enough to set off the breath test and cause a false reading. Diabetics are more likely to have this issue, since their breath may have acetone in it if they are hypoglycemic.
The problem with hypoglycemia, specifically, is that it has other symptoms that mimic alcohol intoxication. For example, someone who is hypoglycemic may have jerky movements or be confused. He or she may be dizzy, shaky or clumsy. Unfortunately, hypoglycemia is a medical emergency for many people. Believing that the person is drunk delays a correct diagnosis and can put his or her life in jeopardy.
It's not just diabetes that causes hypoglycemia. Other conditions, like cardiac events or liver disease, can also cause the body to go into a hypoglycemic state. Overexertion and anxiety have the potential to cause this condition as well, so even if the driver isn't diabetic, he or she could still be suffering from hypoglycemia. Interestingly, dieting or fasting can also cause the level of acetone to rise in the breath, which results in false Breathalyzer readings.
People who are prone to hypoglycemia should wear medical alert bracelets and carry medical alert cards in their purses or wallets. This helps others identify when they need help, so emergency care can be administered.
Source: Alcohol Problems and Solutions, "False Breathalyzer Results from Acetone in Breath: Breathalyzers often Give Inflated Readings," accessed Oct. 19, 2017