Specimen Name Result Units Range
Plasma Sodium 144 mmol/L (135-145)
Potassium 3.6 mmol/L (3.5-5.5)
Chloride 100 mmol/L (100-109)
Bicarbonate 29 mmol/L (22-32)
Glucose 5.0 mmol/L (3.8-5.5)
Urea 2.8 mmol/L (2.7-7.2)
Creatinine 90 μmol/L (60-110)
Osmolality 371 mmol/kg (275-295)

20yo male with confusion / stuporous.
High Osmolar Gap
  • Osmolar gap (measured - calculated osmo):
    • calculated ≈ 1.86*(Na+K) + urea + glucose + 10
    • usually ≤ 10 (can be ≤ 24)
    • gap (meas - calc) : (371 - 292) ≈ 79mmol/kg
  • BAL : 0.29% (0.01% ≈ 2.0 mmol/L) ≅ 58 mmol/L
     
  • NB: OG > 25 → >80% specific for toxic alcohol ingestion

 

Aetiology:

  • alcohols
    • ethanol, methanol
    • mannitol, sorbitol
    • propylene glycol
  • hyperlipidaemia
  • hyperproteinaemia
  • glycinaemia - post-TURP syndrome