The purpose of this study is to collect blood and urine samples that may help identify and validate biomarkers for the early detection and risk assessment of acute kidney injury (AKI).

Inclusion Criteria:

Males and females 21 years of age or older;

Subjects enrolled (first sample collection) from ED or Floor admitted to the ICU within 24 hours of enrollment; Subjects enrolled from ICU admitted to the ICU within the 24 hours prior to enrollment; Expected to remain in the ICU for at least 48 hours after enrollment; Use of indwelling urinary catheter as standard care expected for at least 48 hours after enrollment; At least one of the following acute conditions within 24 hours prior to enrollment:

(Respiratory SOFA score of ≥ 2 (PaO2/FiO2 <300)and/or Cardiovascular SOFA score of ≥ 1 (MAP < 70 mm Hg and/or any vasopressor required).

Patient (or authorized representative) able and willing to provide written informed consent for study participation.

Exclusion Criteria:

Special populations including women with known pregnancy, prisoners or institutionalized individuals;Previous renal transplantation;Known acutely worsening renal function prior to enrollment (e.g., any category of RIFLE criteria. Already receiving dialysis (either acute or chronic) or in imminent need of dialysis at the time of enrollment; Known infection with human immunodeficiency virus (HIV) or active hepatitis (acute or chronic);Patient meets any of the following:Active bleeding with an anticipated need for > 4 units PRBC;Hemoglobin < 7 g/dL;Any other condition that in the physician's opinion would contraindicate drawing serial blood samples for clinical study purposes.

Adult ICU patients at risk for AKI.