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HelpTest Code OSMO Osmolality, Serum
Additional Codes
LAB107
Performing Laboratory
Central Peninsula Hospital
Collection Method
Venipuncture
Container
Gold Top / Serum Separator / Additive Free
Specimen Type
Gold Top SST or Red Top
Minimum Volume
0.5ml
Specimen Stability
| Ambient | 3 hours |
| Refrigerated (4°C to 8°C) | 10 hours |
| Frozen(-40°C to 0°C) | 3 days |
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.
Reference or Target Ranges
275-295 mOsm/kg
Reportable Units
mOsm/kg of H2O
Critical Value
≤265mOsm/kg
≥320 mOsm/kg
Reasons for Rejection
| Hemolysis Threshold | No interference |
| Icterus Threshold | Not listed |
| Lipemia Threshold | Not listed |
| Other | QNS, contaminated, improperly labeled, improper specimen type |
Performance Information
| Days and Time Performed | 24/7 |
| Expected Turn Around Time |
Stat: 1 hour Routine: 4 hours |
| Stat Availability | Yes |
| Performing Bench | CPH Chemistry |
| Methodology/Method Description | Advanced Instruments Micro-Osmometer Model 3320 – Uses the technique of freezing-point depression to measure osmolality |
CPT Codes
83930
Last review/edit date
2025