Preferred Sample Type
Suitable Specimen Types
Plain Spot UrineUrine Osmolality
Specimen Volume
0.5 mLSample Preparation
Please use a plain universal (no preservative) for this test.
Turnaround Time
1 Day (Please contact the laboratory if urgent)Sample Processing In Laboratory
All serum and urine samples must be analysed within 24 hours of receipt into the laboratory.Sample Stability
5 days at room temperature, 4 days at 4°CGeneral Information
Determination of plasma and urine osmolality are used in the assessment of electrolyte and acid-base disorders. Comparison of plasma and urine osmolalities determines the appropriateness and status of water regulation by the kidneys in settings of severe electrolyte disturbances, as might occur in diabetes insipidus or the syndrome of inappropriate secretion of antidiuretic hormone (SIADH).
For the differential diagnosis of hypo and hypernatraemia, urine electrolytes should be requested along with urine osmolality.
Patient Preparation
None
Reference Range
None Given
Specifications
- EQA Status: UK NEQAS Urine Chemistries Scheme
- EQAS Scheme: Yes