Water Loading Test:

Test is started 2 hours after patient has eaten light breakfast.
· 8.00am: Patient is given a light breakfast.
· Plasma and urine osmolality are measured.
· 8.30 am: Patient is given water to drink (20 ml/kg) over 15 to 30 minutes; light salted crackers
may be given with water if needed.
· Patient is kept in recumbent position.
· 10.30 am: Collect all urine that is passed out for urine volume and osmolality measurements and
blood sample is also taken for plasma osmolality
· Repeat specimen collection as above every hour for next 4 hours (11.30am, 12.30pm, 1.30pm and
2.30pm) and label all containers with patient information and time collected.