The objective of this sample collection study is to collect blood and urine samples. This study is observational and will have no impact on the medical management of the subject.

Inclusion Criteria:

• Males and females 21 years of age or older
• Subjects must be enrolled (first study-specific sample collection) within 24 hours of ICU admission
• Subjects enrolled from ED or Floor must be admitted to the ICU within 24 hours of enrollment
• Subjects enrolled in the ICU must have been admitted to the ICU or transferred into the study ICU from another ICU no more than 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 documented within 24 hours prior to enrollment
• Respiratory SOFA score of ≥ 2 (PaO2/FiO2 <300)
• Cardiovascular SOFA score of ≥ 1 (MAP < 70 mm Hg and/or any vasopressor required
• Subject (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 moderate to severe AKI prior to enrollment (e.g., RIFLE-I or RIFLE-F/ AKIN 2 or AKIN 3
• 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)
• Subjects with a history of Chronic Kidney Disease (CKD) without a baseline serum creatinine value (baseline within 6 months of enrollment)

Adult patients at risk of AKI.