<unk>  measures the body's electrolyte–water balance. There are several methods for arriving at this quantity through measurement or calculation.<unk> olality and<unk> olarity are measures that are technically different, but functionally the same for normal use. Whereas<unk> olality (with an "l") is defined as the number of<unk> oles <unk>  of solute per kilogram of solvent <unk> ol/kg or<unk> /kg),<unk> olarity (with an "r") is defined as the number of<unk> oles of solute per liter (L) of solution <unk> ol/L or<unk> /L). As such, larger numbers indicate a greater concentration of solutes in the<unk> .
Plasma osmolality
Urine osmolality
Cerebral perfusion pressure
Intracranial pressure
Mean arterial pressure
Serum chloride
Glomerular filtration rate
Urine sodium