This study examines the relationship between D-dimer concentration and patient age, gender, race, and renal function, and the role of D-dimer concentration as a predictor of in-hospital mortality, in a critically ill patient population. The results demonstrate there is a correlation between increased D-dimer concentration and renal impairment in critically ill patients, with patients in renal failure having the highest D-dimer concentrations. Peak D-dimer levels were higher among female patients than in male patients, but there was no association between peak D-dimer levels and other patient characteristics. D-dimer concentration was also not predictive of in-hospital mortality.