Category of hyponatremia based on serum osmolality and plasma sodium

Condition	Serum osmolality	Plasma sodium concentration by direct ion-selective electrode (point-of-care device or blood gas machine)
Hypotonic hyponatremia	Low^¶	Low
Nonhypotonic hyponatremia due to endogenous solutes: Hyperglycemia	High	Low
Nonhypotonic hyponatremia due to exogenous solutes: IV mannitol Absorbed surgical irrigants Therapeutic immunoglobulins*	Normal or high	Low
Pseudohyponatremia Lipemic serum Jaundice^Δ Hyperproteinemia (multiple myeloma)	Normal	Normal

IV: intravenous; BUN: blood urea nitrogen.

* Therapeutic immunoglobulins are suspended in solutions of hypertonic maltose or sucrose that cause hyponatremia in a similar manner as IV mannitol; there may also be a small component of pseudohyponatremia due to the development of hyperproteinemia.

¶ Elevated BUN or blood alcohol levels can result in a misleadingly normal or high osmolality despite true hypotonic hyponatremia.

Δ Caused by elevated lipoprotein X levels.

Graphic 140256 Version 2.0

خرید پکیج

Category of hyponatremia based on serum osmolality and plasma sodium