Thousands of blood alcohol test results were called into question in Wisconsin because of a phenomenon dubbed “jagged humps” that has been observed in one blood testing lab. The science behind headspace gas chromatography tests is complex and the details can be found here, but in essence these jagged humps are unexplained anomalies in the results of blood alcohol tests that are present in all three of Wisconsin State Laboratory of Hygiene’s instruments. These jagged humps could possibly invalidate the test results.
Given that it is unknown why the jagged humps appear in the test results or even what they represent, it is hard to predict the impact these anomalies will have on the thousands of DUI cases possibly affected. More pertinently, if it turns out that the humps are inherent to all similar instruments (or even process of headspace gas chromatography as a whole), as opposed to being particular to that Wisconsin Lab, the validity of similar test results all across the country could be called into question.