In the post-liver transplant care unit, we observed several instances in which patients exhibited normal prothrombin time but disproportionately prolonged clotting time (CT), as measured by Rotational Thromboelastography (ROTEM). Hence, we conducted a case series in patients with reduced maximum clot firmness (MCF) in ROTEM. Platelets and fibrinogen concentrate were incrementally added to the blood samples in vitro in three tubes, with incremental doses from tubes 1 to 3, and ROTEM was repeated for each tube. Blood samples from six patients were analysed, with each patient undergoing one baseline ROTEM and three subsequent ROTEM tests following in vitro correction, resulting in a total of 24 observations (six baseline and 18 repeat ROTEM). Except for three instances, all repeat ROTEM values showed improvements in CT, along with Clot formation time (CFT) and MCF, from baseline to tube 3. Regression analysis of the 18 delta values suggested that for every 100-second increase in CFT, there was an associated 10-second increase in the CT. We conclude that a critically prolonged CFT and low MCF can result in falsely prolonged CT in ROTEM.