Adini, et al., have advanced the measurement of health care emergency preparedness. With limited resources, the necessity to find commonalities of approach and efficiency in all we do, including measurement, is critical. In the end, a set of validated preparedness measures would support the dual goals of accountability and improved outcomes and could provide the basis for determining which actions in the name of preparedness really make a difference. Presentation of hemophagocytic lymphohistiocytosis due to a novel MUNC 13–4 mutation masked by partial therapeutic immunosuppression Hemophagocytic lymphohistiocytosis is a potentially fatal disease characterized by excessive macrophage and lymphocyte activity. Patients can be affected following immune activation after an oncologic, autoimmune or infectious trigger. An associated gene mutation may be found which impairs cytolytic lymphocyte function. We describe a pediatric case of hemophagocytic lymphohistiocytosis with a novel mutation of MUNC 13–4 whose diagnosis was confounded by concurrent immunosuppression. Clinical reassessment for hemophagocytic lymphohistiocytosis is necessary in persistently febrile patients with laboratory derangements in the setting of immunosuppressive agent exposure. Hemophagocytic lymphohistiocytosis (HLH) is a clinical syndrome of abnormal immune activation causing excess inflammation. There is increased ectopic migration and proliferation of T cells, tissue infiltration by activated macrophages (histiocytes), hyper-activation of lymphocytes, and prolonged release of pro-inflammatory cytokines [1] . This leads to uncontrolled inflammation manifesting as fever, cytopenias and organ dysfunction. The syndrome is fatal without prompt symptom recognition and treatment.