What is the definition or description of: low sodium?

Hyponatremia: Is an electrolyte disturbance in which the sodium concentration in the serum is lower than normal. Its homeostasis is vital to the normal physiologic function of cells. Normal serum sodium levels are between 135 and 145 meq/l. Hyponatremia is defined as a serum level of less than 135 meq/l and is considered severe when the serum level is below 125 meq/l.

Low sodium < 135: Normal sodium range from 135 to 145. Low sodium (hyponatremia) is less than 135. Some may have no symptoms at slight decrease in sodium level especially if the level dropped slowly. Rapid decrease or large drop in levels can cause confusion, seizures, coma and even death. Labs should always be rechecked to exclude false abnormal level.