For clinical reference only — does not replace local trust guidelines or clinical judgement.
‹ Blood Results
Blood Results

Raised Urea

Raised Urea

Severity
Range
  • Mild
    Urea 8–15, normal creatinine
  • Moderate
    Urea 15–25 or out of proportion to creatinine
  • Severe
    Urea > 25, uraemic features, or AKI
💧

Pre-renal (volume / perfusion) Causes

Dehydration — poor intake, fevers, hot weatherGI losses — vomiting, diarrhoea, NG, stoma, fistulaDiuretic excessSepsis / distributive shockCardiac failure, hepatorenal syndrome
🩸

GI bleed (high urea : Cr) Causes

Peptic ulcer, varices, Mallory-WeissNSAID / steroid gastritisOccult upper GI malignancySwallowed blood from epistaxis
🫘

Renal (intrinsic) Causes

Acute tubular necrosisAcute interstitial nephritis (PPI, NSAID, antibiotic)Glomerulonephritis, vasculitisChronic kidney disease baseline rise
🚽

Post-renal / obstruction Causes

Prostatic enlargement, blocked catheterPelvic malignancy, bilateral ureteric stonesRetroperitoneal fibrosis
🍽️

Protein load / catabolic Causes

High-protein diet, TPNSteroids, tetracyclinesGI bleed (digested blood = protein load)Severe sepsis, trauma, burns (catabolism)