Test Directory

Test Code
OSM
Test Name
Osmolality, Serum
CPT Codes
83930
Expected Turnaround Time
1 day
Clinical Utility

Can be used to evaluate electrolyte, water and acid/base balance; hyperosmolar and hydration status; and to aid in the screen for the presence of certain low molecular weight toxins.

Specimen and Container Info

Specimen Types: Serum or Plasma

Collection Containers:

  • Gold Top, Serum Separator
  • Light Green Top, Plasma Separator
  • Red Top, Separator

Minimum Acceptable Volume: 1.0 mL

Processing and Submission Instructions

Separator tubes: Contains clot activator and gel for separating serum from cells, but not anticoagulant. Separate serum from cells as soon as the clot has formed (30 minutes). If specimen is centrifuged before clotting is complete, a fibrin clot will form on top of the cell. This may cause the gel barrier to not be intact and could cause improper separation of serum and cells, possibly affecting test results.

Tubes with anticoagulant: To ensure accurate test results, all tubes containing an anticoagulant or preservative must be allowed to fill completely. Attempts to force more blood into the tube by exerting pressure, as in collection with a syringe, will result in damage to the red cells (hemolysis).

Transport Instructions

Transport to the laboratory refrigerated.

Stability Requirements

Refrigerated

7 days

Methodology
Freezing-Point Depression
Reference Intervals
Critical Values
Performing Location
Cedar Crest Hospital, Hazleton Hospital, Hecktown Oaks Hospital, Muhlenberg Hospital, Pocono Hospital, Redeemer Health
Testing Schedule
Routine, daily