There is provided a method of evaluating a liver condition of a subject, the method includes computing a fluctuation parameter from a liver breath test based on at least one of a percentage dose recovery (PDR) curve and a delta over baseline (DOB) curve of an isotope labeled methacetin, or a salt or a derivative thereof, and evaluating at least one liver condition of the subject, based at least on the fluctuation parameter. There is provided herein a method of evaluating a liver condition of a subject, the method includes computing a hepatic impairment score based at least on a breath test related parameter and on a demographic parameter.