is a hand held Digital Refractometer calibrated from 0 to 1500
mOsmols/kgH2O which equates to a specific gravity of 1.000 to 1.043
or a refractive index of 1.333 to 1.350
This relationship has been derived empirically from a selection of
70 different urine samples (as shown in the graph below).
For true Osmolality results an Osmometer, such as the Advanced
Micro Osmometer, model 3320, should be used.
Early morning urine samples are recommended. Readings above 600m
Osmols indicate that rehydration is advisable, and over 800 m
Osmols that it is essential.