<sod>The BUN:Cr in postrenal azotemia is initially >15. Over time the BUN:Cr will decrease due to tubule epithelial damage.<ref>{{cite web|url=http://www.consultation.ayurvediccure.com/types-of-azotemia/|title=Types of Azotemia |website=AyurvedicCure.com}}</ref> The increased [[nephron]] tubular pressure causes increased reabsorption of urea, elevating it abnormally relative to creatinine.<ref name=goljanpath /><eod>
<sod>The BUN:Cr in postrenal azotemia is initially >15. The increased [[nephron]] tubular pressure (due to fluid back-up) causes increased reabsorption of urea, elevating it abnormally relative to creatinine.<ref name="goljanpath" /> Persistent obstruction damages the tubular epithelium over time, and renal azotemia will result with a decreased BUN:Cr ratio.<ref>{{cite web|url=http://www.consultation.ayurvediccure.com/types-of-azotemia/|title=Types of Azotemia |website=AyurvedicCure.com}}</ref> <eod>