Methods and compositions for diagnosis and prognosis of renal injury and renal failure

A method for evaluating renal status in a subject that meets the definition of RIFLE I or F for persistence of acute renal injury, comprising:

• performing an assay method configured to detect Chitinase-3-like protein 1 on a body fluid sample obtained from the subject to provide an assay result by introducing the body fluid sample obtained from the subject into an assay instrument which (i) contacts all or a portion of the body fluid sample with a binding reagent which specifically binds for detection Chitinase-3-like protein 1, and (ii) generates an assay result indicative of binding of Chitinase-3-like protein 1 to its binding reagent;
• correlating the assay result to the renal status of the subject by using the assay result to assign the patient to a predetermined subpopulation of individuals having a known likelihood of recovery from acute renal injury within 72 hours of the time at which the body fluid is obtained, the assignment made by comparing the assay result or a value derived therefrom to a threshold value obtained from a population study, wherein the threshold separates the population into a first subpopulation above the threshold and a second subpopulation below the threshold, the second subpopulation being at an increased likelihood persistent acute renal injury relative to the first subpopulation;
• and
• treating the patient based on the predetermined subpopulation of individuals to which the patient is assigned, wherein when the assay result or value derived therefrom assigns the subject to the second subpopulation, the subject is treated for persistent acute renal injury by initiation or continuation of renal replacement therapy.