The amount of time that alcohol stays in someone’s system depends on numerous factors including gender, physical composition (body fat, etc.), age, whether food was eaten, and genetic make-up.
On average, alcohol will be detectable on the breath for about 24 hours. In blood tests, alcohol will be observable for around 12 hours, while urine tests can pick up alcohol for up to 2-3 days. Alcohol tests that assess hair composition can detect alcohol for around 3 months after consumption.
The vast majority of alcohol must be processed by the liver. A healthy liver can process, on average, one drink per hour.