Specimen Name Result Units Range
Plasma Sodium 140 mmol/L (135-145)
Potassium 5.0 mmol/L (3.5-5.5)
Chloride 107 mmol/L (100-109)
Bicarbonate 21 mmol/L (22-32)
Anion Gap 17 mmol/L (7-17)
Glucose 5.8 mmol/L (3.8-5.5)
Urea 37 mmol/L (2.7-7.2)
Creatinine 640 μmol/L (60-110)
Osmolality 323 mmol/kg (275-295)
Urine Sodium 74 mmol/L (> 20)
Osmolality 305 mmol/kg

60yo male admitted with urinary retention ∝ prostatomegaly.
Post-obstructive ARF
  • significant AKI 2° obstruction
  • post-obstruction polyuric phase:
    • ∝ persistent loss of concentrating ability
    • → hypovolaemia
  • osmolality >320 mosm/kg → urine should be maximally concentrated