Predicting Worsening Acute Kidney Injury With a Water-Pill (Furosemide) Test and Blood Markers in Patients With Low Albumin

The goal of this clinical trial is to learn if serum biomarkers can better predict worsening of acute kidney injury (AKI) compared to the Furosemide Stress Test (FST) in adult patients with low albumin levels (hypoalbuminemia) admitted to an intensive care unit (ICU). The main questions it aims to answer are: Can serum biomarkers predict progression to severe AKI (stage 3) better than the Furosemide Stress Test in patients with low albumin levels? Is there a relationship between serum biomarkers levels and serum albumin levels in these patients? Researchers will compare serum biomarkers levels and FST results to see which test more accurately identifies patients at risk of developing severe AKI. Participants will: Provide a sample for serum biomarkers measurement at study entry Receive a single intravenous dose of furosemide (a diuretic medication) to assess kidney function Have their urine output monitored for 6 hours after the furosemide dose Be followed for 15 days to track kidney function, need for dialysis, and survival

Inclusion Criteria: * Age 18 years or older * Serum albumin \< 3 g/dL (hypoalbuminemia) * AKI diagnosed per KDIGO 2012 criteria, stage 1 or 2 * Adequate fluid resuscitation at discretion of treating nephrologist * Cellular casts in urinary sediment (George Washington Urine Sediment Score \> 2) or fractional excretion of sodium (FENa) \> 1% * Foley catheter in place * Written informed consent obtained Exclusion Criteria: * Age under 18 years * Pregnancy * Obstructive urinary pathology * Active bleeding * Allergy or hypersensitivity to loop diuretics * AKI stage 3 (KDIGO) at enrollment * Inadequate fluid resuscitation prior to the stress test * Known chronic kidney disease with eGFR \< 30 mL/min/1.73 m² (CKD-EPI equation)