Osmolality, serum
Clinical Background:
Serum osmolality is a useful initial test when investigating the cause of hyponatraemia and in identifying a raised osmolal gap for suspected poisoning.
Calculated osmolarity = 2 (Na+) + glucose + u...
Serum osmolality is a useful initial test when investigating the cause of hyponatraemia and in identifying a raised osmolal gap for suspected poisoning.
Calculated osmolarity = 2 (Na+) + glucose + urea
The difference between the measured osmolality and the calculated is known as the osmolal gap and is normally less than 10 mOsm/kg.
Test Details
-
Discipline:
Biochemistry
Biochemistry
-
Specimen Container Adult:
Serum (SST or plain tube)
Serum (SST or plain tube)
-
Specimen Container Paediatric:
Serum (SST or plain tube)
Serum (SST or plain tube)
-
Minimum Volume Adult:
1 mL blood
1 mL blood
-
Minimum Volume Paediatric:
0.5 mL blood
0.5 mL blood
-
Sample Stability:
Unseparated sample: Unknown
Separated samples:
12 hrs at 20-25C
3 days at 4-8C
3 months at -20C
Unseparated sample: Unknown
Separated samples:
12 hrs at 20-25C
3 days at 4-8C
3 months at -20C
-
Reference Ranges:
275-295 mmol/Kg
275-295 mmol/Kg
-
Routine Contact Name:
Duty biochemist
-
Routine Telephone:
Freeman: 0191 244 8889
RVI: 0191 282 9719Freeman: 0191 244 8889
RVI: 0191 282 9719 -
Routine Email: