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Test Code BLOD0617 Osmolality, Serum

Useful For

  • Determining the number of solutes present in serum and urine
  • Evaluating the body's water balance or its ability to produce and concentrate urine
  • Investigating low sodium levels
  • Detecting the presence of toxins such as methanol and ethylene glycol
  • Monitoring osmotically active drug therapies such as mannitol, used to treat cerebral edema
  • Monitoring the effectiveness of treatment for any conditions found to be affecting a person's osmolality


Freezing Point Depression

Performing Laboratory

Bozeman Health Laboratory Services

Specimen Requirements

Specimen Type: Serum
Container/Tube: Red top or gold top
Specimen Volume: 2 mL
Specimen Minimum Volume: 1 mL

Specimen Transport Temperature


Specimen Stability


Specimen Type Temperature Time
Serum Ambient 4 hours
  Refrigerated 5 days
  Frozen 6 months


Reference Values


Age Reference Values
0-7 days 275-300 mOsm/kg
7-28 days 276-305 mOsm/kg
28 days-2 months 274-305 mOsm/kg
>2 months 275-295 mOsm/kg


Day(s) Test Set Up

Monday through Sunday

Test Classification and CPT Coding