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Test Code OSMO BF Body Fluid Osmolality

Clinical System Name

Body Fluid Osmolality

Sample Requirements

Specimen:  Body Fluid

Container(s): Sterile Screw-Capped Container, Sterile Screw-Capped Tube or Syringe

Preferred Vol: 0.5 mL

Minimum Vol: 0.25 mL body fluid


Note: Note type of body fluid on requisition. Sample should not have cells present and should be at room temperature before testing.

Processing Instructions

Reject due to: Age of Specimen

Spin: Y

Aliquot: Y

Temp: 2-8oC

Storage location: Core 5 Chemistry Refrigerator


Off-site collection: Send 1 - 2 mLs refrigerated (2-8oC) supernatant in a sterile container. Note type of body fluid on requisition.



Specimen Type Temperature Time
Body Fluid RT

 4 H

Body Fluid 2-8oC

≤ 24 H

Body Fluid -20oC or -70oC

 30 D



STAT Performed TAT
Y 24/7 1 H


Performing Laboratory

Seattle Children's Laboratory    


Department:  Core Chemistry

Phone Number: 206-987-2617


Method:  Freezing Point Depression by Fiske micro-Osmometer model 210

Analytical Volume:  0.2 mL

CPT Codes