Osmolality

Alternative Names/Synonyms
Laboratory	Core Laboratory & Transfusion Medicine
Sub-section	Biochemistry
Specimen Type	Blood
Test Code	OSMS, OSMP

Clinical Significance (If applicable)

Assisting in the diagnosis and monitoring of electrolyte and/or water balance disorders.

Identifying the presence of toxic alcohol as part of the Osmolar Gap calculation.

Specimen Requirements (Sample Type)

Serum, Plasma

Specimen Requirements (Volume (mL))

0.5 mL

Specimen Requirements (Tube Type)

Serum (Gold SST)
Plasma (Light Green PST)
Collection Containers – Tube Types

Draw (mL)

4.5 mL

Collection Requirements

Collection Instructions

Cause for Rejection

Specimen Acceptability and Transport Guidance

Instrument, Methodology

Osmo1 Osmometer, freezing point depression

Test Availability

24 hours a day, 7 days a week

STAT Turnaround Time

1 hour

Routine Turnaround Time

1 hour

Reference Ranges

280 - 300 mOsm/kg
In case of discrepancies, always interpret results using reference ranges as stated on laboratory reports and/or electronic patient chart.

Laboratory Contact Information

416-586-4800 extension 4688