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Test Code Osmo Osmolality

Patient Preparation

No special patient preparation required

Collection Method

Venous collection

Minimum Volume

0.1 mL

Container

Gold Top / Serum Separator / Additive Free

Preferred Specimen

Gold Top SST

Acceptable Specimens

Serum:

  • Gold Top SST
  •  
  • Red Top

Plasma

  • Light Green Top (lithium heparin)

Reference or Target Ranges

Neonate as low as 266 mOsm/kg of H2O
Child to 60 years 275 – 295 mOsm/kg of H2O
>60 years 280 – 301 mOsm/kg of H2O

Reportable Units

mOsm/kg of H2O

Critical Value

<250 mOsm/kg or >340 mOsm/kg

Reasons for Rejection

 


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Hemolysis Threshold No interference
Icterus Threshold Not listed
Lipemia Threshold Not listed
Other QNS, contaminated, improperly labeled, improper specimen type

Specimen Stability

 


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Ambient 3 hours
Refrigerated (4°C to 8°C) 10 hours
Frozen(-40°C to 0°C) 1 week

Performance Information

 


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Days and Time Performed 24/7
Expected Turn Around Time Stat: 1 hour
Routine: 4 hours
Stat Availability Yes
Performing Bench UH Chemistry
Methodology/Method Description Advanced Instruments Micro-Osmometer – Uses the technique of freezing-point depression to measure osmolality

Special Handling

If testing delayed, refrigerate or freeze ASAP to prevent a change in the original osmolality due to evaporation of H2O, decomposition or combination of solutes. Prior to analysis, specimens must equilibrate to room temperature and be gently mixed to aid the complete solution of any precipitated solutes.

CPT Codes

83930