Osmolality is a measure of how much one substance has dissolved in another substance. The blood osmolality test is also known as a serum osmolality test. Serum is the liquid part of your blood. The serum test is used mainly to evaluate hyponatremia, a below normal level of sodium in the bloodstream.
Doctor may order a blood osmolality test to check body’s salt/water balance.
The reference range of serum osmolality is 275–295 mosm/kg (mmol/kg).
