Table 5.

Tests for Idiopathic Edema12,30,31,52

Morning and Evening Weights: Patients should weigh themselves nude and with an empty bladder before food or fluids in the morning and at bedtime. A mean weight gain >0.7 kg is consistent with idiopathic edema.
Water Load Test: After avoiding diuretics for at least 10 days, the patient drinks 20 mL/kg body weight (maximum 1500 mL) uniced water over 20 minutes, sometime between 7:30 AM and 9:00 AM. The patient collects urine every hour, starting 1 hour before the oral fluid load and ending 4 hours after. On the first day, the patient should be walking slowly or standing during this 4-hour period. On the second day, the patient repeats the fluid load and urine collection, but should be recumbent during the 4-hour period. In patients with idiopathic edema, less than 55% of water load is excreted in the upright position and more than 65% in the recumbent position.