Osmolality | KK Women's and Children's Hospital

Specimen Container	Gel separator tube (Adult) Microtube (Paeds)
Specimen Requirement	Plain Blood Adult: 3 mL Paediatric: 1.3 mL Invert blood 5 times after blood collection ensures the clot-activating factors is well mixed with the blood. This will ensure results are reliable.
Orderable as Urgent?	Yes
Turn Around Time	Average 2 hrs (1 - 3 hrs)
Reference Value(s)	275 - 300 mOSM/kg
Testing Laboratory Location	KKH
Laboratory	Clinical Chemistry
Contact Number	6394 1383
Day and Time Performed	Mon – Fri 0800 hrs– 1700 hrs , Sat 0800 hrs – 1230 hrs
Orderable on CPOE?	Yes
Downtime Form	Clinical Chemistry - Form A
Additional Information	Critical Value: <200 mOsm/kg (Low) and >350 mOsm/kg (High)

Change History Notes

Last Updated - 19 Jun 2025