What Are Some of the Causes of Pseudo Hyponatremia?

If you have a serum osmolality of less than 275ml per kilogram, it would be considered true hyponatremia. If the serum osm is 275 to 290, this would be considered normal. The other interesting case is hyperglycemia, which often gets grouped in with these as not true Hypo-osmolar hypon atremia. What has happened here instead is that water has moved out of the cells due to the high glucose creating a hypertonic environment in the extracellular space.