Blood alcohol level or concentration measured in milligrams (mg) per 100 milliliters (mL) of plasma, but expressed somewhat differently in common medical and legal parlance. For example, a BAL of ".08" means a concentration of 80 mg/100 mL. In a healthy person, one standard drink raises the BAL about 20 mg/100 mL. The body metabolizes alcohol at a rate of about 20 mg/hour.