Background: Classic mortality prediction models in intensive care units (ICUs) are based on clinical scores, which do not contain any coagulation test (SAPS‐II or SOFA scores). Objectives: To determine whether coagulation tests can improve mortality prediction in patients with septic shock. Patients and methods: One hundred fifty‐eight consecutive patients with septic shock entering our institution’s ICU were investigated on the first day of admission, and deaths were registered during the first month. Results: Among all the coagulation tests performed, only the fibrinogen (Fg) plasma level, together with the SAPS‐II score and the age, were included in our simplified mortality score [area under the receiver operating curve (AUC) 0.927, standard deviation (SD) 0.030], which was more efficient than SAPS‐II and SOFA scores themselves in predicting first‐week mortality, its optimized cut‐off having a very high negative predictive value (NPV) [0.989; 95% confidence interval (CI) 0.967–1.000)]. A simplified score predicting first‐month mortality, containing the prothrombin ratio and the antithrombin activity values in addition to the age, the hemoglobin concentration, and the SAPS‐II and SOFA scores (AUC 0.889, SD 0.026), was found to be superior to the SAPS‐II and SOFA scores, the optimized cut‐off value having a high NPV (0.952; 95% CI 0.888–1.000). Conclusions: In patients admitted to an ICU with septic shock, some initial coagulation test values can help identify those who will survive in the first week and then in the first month.
