This will be a two-arm cross-sectional control-cohort outpatient evaluation. Subjects with sAKI and control subjects (age and gender matched) will be recruited from neurology service. Subjects will be asked to come in to the Clinical Research Center for 24-hour monitoring and participate in the outpatient study where urinary and serum studies to measure glomerular filtration rate, renal plasma flow followed by blood pressure monitoring, peripheral arterial and applanation tonometry.