This is a multi-center, prospective, observational study of patients that are admitted to the intensive care unit (ICU). This study does not include any treatment or intervention and it is considered Nonsignificant Risk.

The study will be conducted in two phases. Phase One is specimen acquisition and subject diagnosis adjudication. Phase Two is biomarker testing.

Phase One

Approximately 850 adults admitted to general ICUs will be enrolled within 12 hours of receipt of ICU admission orders. Study specific whole blood and urine specimens will be collected.

There is an Adjudication Committee for this study. This committee is comprised of qualified, board-certified nephrologists.

Phase Two

During Phase Two, the plasma specimens will be divided amongst three clinical sites representative of the intended end users of this assay, and tested under a separate testing protocol.

Inclusion Criteria:

• Subjects must be 21 years of age or older.
• Subjects must be admitted to an Intensive Care Unit (medical or surgical) and must be enrolled into this study within 12 hours of receipt of ICU admission orders.
• Subjects must be assessed as likely to be alive in the ICU for a minimum of 48 hours after enrollment.
• The following plasma/serum creatinine values must be available:
• Subjects that are admitted to the ICU following an elective surgery or procedure must have at least one pre-surgical/ pre-procedure creatinine value obtained in the 7 days prior to presentation to the ICU.
• Subjects that are admitted to the ICU for any reason other than following an elective surgery or procedure must have at least one creatinine value obtained greater than 7 days and up to 6 months prior to presentation to the ICU.

Exclusion Criteria

• Subjects either receiving or in imminent need of Renal Replacement Therapy.
• Subjects with evidence of chronic kidney disease stages 4 and 5 as evidenced by a pre-enrollment estimated GFR of less than 30 mL/min/1.73M2 (according to the 4-variable MDRD22).
• Subjects with any obstructive uropathy at the time of presentation to the ICU.
• Subjects with any known urothelial, urological or kidney malignancies.
• Subjects that have had any urologic procedure or surgery immediately prior to admission to the ICU.
• Subjects that have had any renal transplant or nephrectomy.
• Subjects that have had cardiovascular surgery involving cardiopulmonary bypass within the previous 7 days.
• Subjects that have participated in an interventional clinical study within the previous 30 days including studies with any investigational and non-investigational drugs.
• The inability to obtain written Informed Consent from the subject or an authorized representative.
• Subjects that have been previously enrolled in this study during a prior admission to the ICU.

All comers ordered to be admitted to the ICU.