The diagnostic algorithm for sepsis-induced coagulopathy (SIC) and disseminated intravascular coagulation (DIC). The presence of SIC or DIC needs to be carefully evaluated in patients with sepsis who develop thrombocytopenia. As the first step, the presence of SIC is checked by using the scoring system for SIC (table 1), and if it is determined to be present, the presence of overt DIC should be confirmed (table 1) in the second step. When neither SIC nor DIC is found to be present, thrombotic microangiopathy (TMA) and other conditions should be considered as the cause of the thrombocytopenia. As a first step, the presence of microangiopathic hemolytic anemia (MAHA: erythrocyte fragmentation, elevated lactate dehydrogenase, elevated bilirubin, decreased hemoglobin [less than 10 g/dl], and depleted haptoglobin) is examined, and if it is found to be present, the presence of thrombotic thrombocytopenic purpura (TTP), Shiga toxin-producing Escherichia coli (STEC)–induced hemolytic uremic syndrome (HUS), atypical HUS (aHUS), and secondary TMA should be considered. If MAHA is excluded, other conditions such as heparin-induced thrombocytopenia (HIT) and immune thrombocytopenia (ITP) should be considered. APS, antiphospholipid syndrome; CAPS, catastrophic APS.