 Many approaches have been studied in relation to this concept. Deterioration in renal function is a harbinger of a need for hospitalization, and indeed a predictor of medium term mortality. However, current measures of renal function are relatively crude with a considerable lag between an insult to the kidney and its translation to a measurable deterioration in renal function reflected by worsening serum creatinine. Thus, diagnostic tests that evaluate renal injury which are modulated early in the time course of this process may have considerable utility not only in the ADHF setting but also in predicting decompensation in the CHF setting. 