This site is intended for healthcare professionals

Go to /sign-in page

You can view 5 more pages before signing in

Classification of hyponatraemia

Last reviewed dd mmm yyyy. Last edited dd mmm yyyy

Authoring team

Hyponatraemia can be classified according to the serum sodium concentration (1):

  • Mild — serum sodium concentration 130–135 mmol/L.
  • Moderate — serum sodium concentration 125–129 mmol/L.
  • Severe — serum sodium concentration less than 125 mmol/L

Classification according to volume status:

  • hypovolaemic hyponatraemia
  • euvolaemic hyponatraemia
  • hypervolaemic hyponatraemia (2)

Hyponatraemia is also classified according to the rate of onset (although calculating the duration of hyponatraemia is often difficult):

  • acute hyponatraemia - symptoms develop in less than 48 hours
  • chronic hyponatraemia - symptoms present for more than 48 hours (2,3)


Create an account to add page annotations

Add information to this page that would be handy to have on hand during a consultation, such as a web address or phone number. This information will always be displayed when you visit this page