Workup – Osmolal Gap

• Serum osmolality = 349

• Osmolal Gap =

• Measured osmoles – Calculated osmoles

• Calculated osmoles = 2 Na + BUN/2.8 + Glucose/18

• Calculated osmolarity = 2 (142) + 17/2.8 + 382/18 = 311

• Osmol Gap = 349 – 311 = 38