Renal Function Tests (RFT)

Renal

Urea, creatinine and eGFR — distinguish AKI vs CKD, pre/intra/post-renal.
UreaCreatinineeGFRNa/KUrine output

Raised creatinine (AKI)

Common causes

  • Pre-renal: dehydration, sepsis, cardiac failure
  • Intra-renal: ATN, AIN, GN
  • Post-renal: obstruction

Significance: Use KDIGO staging (creatinine rise ≥0.3 in 48h or 1.5× baseline).

Differential diagnosis

  • Pre-renal AKI
  • ATN
  • AIN (drugs)
  • Glomerulonephritis
  • Obstructive uropathy

Next investigations

  • Urine routine + microscopy
  • FENa / FEUrea
  • USG KUB
  • ABG (acidosis)
  • Autoimmune panel if GN suspected

Red flags

  • Hyperkalaemia >6.5
  • Severe acidosis pH <7.2
  • Pulmonary oedema
  • Uraemic encephalopathy

Educational support only — not a substitute for clinical judgment.

WardRound

WardRound

Clinical Decisions in Seconds