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.