Table 1. Scheme for calculating the fluid retention index (FRI), which is the mean of the FR scores for four urinary indexes of fluid retention.

Fluid retention score	1	2	3	4	5	6
Specific gravity	≤ 1.005	1.010	1.015	1.020	1.025	1.030
Osmolality (mosmol/kg)	< 250	250–450	450–600	600–800	800–1000	> 1000
Creatinine (mmol/L)	< 4	4–7	7–12	12–17	17–25	> 25
Color* (shade)	1	2	3	4	5	6

* One score higher was used in the study due to incongruence with the other markers.