However, our previously published clinical studies in the setting of acetaminophen overdose and heparin-induced liver injury reveal that these biomarkers appear to have a shorter half-life than ALT activity (24 hours compared to 48 hours) and return to baseline levels more rapidly than ALT activity.9,10 The utility of these markers at timepoints later than 48 hours is also highlighted in these studies, given their prognostic utility in late-presenting patients with established liver injury. Here, GPT is linked to injury.