Test Code OSMOU Osmolality Urine
Additional Codes
Cerner |
NextGen |
Osmolality Urine |
Osmolality Urine |
Useful For
Osmosis is the process that constitutes the movement of solvent across a membrane in response to differences in osmotic pressure across the membrane. Water migrates across the membrane toward the side containing more concentrated solute. The osmolality of body fluids may be measured in serum or urine. The osmotic pressure is maintained by the charged solutes in the plasma, i.e., sodium, potassium, iron, bicarbonate, chloride, protein, etc. The osmotic pressure must be maintained within fairly narrow range in the water compartments of the body. If the pressure becomes too high, it can result in pressure on the brain and brainstem; too low pressure tends to decrease the structural integrity of solid tissues. The regulation of the osmolality is controlled by thirst and ADH function in the renal tubules.
Methodology
Freezing point depression
Patient Preparation
None
Collection Instructions
- Catheterized specimens collected according to clinical policies and procedures
- Radom clean catch instructions: Random Urine Collection Instructions
- Keep samples capped to avoid evaporation.
Specimen Requirements
Container |
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Stability |
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Rejection Criteria |
Not Defined |
Result Reporting and Reference Values
- 300 - 900 mOsm/kg
- Urine after 12 hr fluid restriction: Should be greater than 850 mOsm/kg.
Reflex Testing
None
Limitations
Not Defined