Researchers in Zurich have developed a saliva test capable of detecting acute sleep deprivation. The test identifies measurable traces of severe fatigue from a single sample. This breakthrough marks the first time sleepiness has been demonstrably linked to a biomarker in saliva. The findings suggest potential applications for law enforcement, particularly in post-accident investigations, such as traffic collisions. Currently, assessing driver fatigue relies on subjective evaluations or lengthy neurological tests. This new test offers a quicker, less invasive method for objective assessment. Further research is needed to refine the test and establish standardized thresholds for fatigue levels.