The major novel findings of our study were that non-surviving septic patients showed persistently higher RDW during the first week of ICU stay than survivors, that RDW during the first week was associated with sepsis severity and mortality, that RDW during the first week could be used to predict outcome in septic patients, and that there was an association between RDW, serum MDA and serum TNF-α levels during the first week. The gene discussed is TNF; the disease is Sepsis.