What is the normal range for serum sodium?

What is the normal range for serum sodium?

• A. 135-145
• B. 125-135
• C. 145-155
• D. 120-130

Answer: (A)

Normal serum sodium is about 135 to 145 mEq/L. This range is the reference for assessing fluid and electrolyte balance because sodium is the main extracellular cation that helps regulate osmotic balance and fluid distribution, with the kidneys and hormones like aldosterone and ADH keeping it within this window. Values below 135 indicate hyponatremia, which can lead to confusion, seizures, or edema in severe cases. Values above 145 indicate hypernatremia, which can cause thirst, confusion, and possible dehydration. Among the options, 125-135 is below normal (hyponatremia), 145-155 is above normal (hypernatremia), and 120-130 is also well below normal, leaving 135-145 as the normal range.

Normal serum sodium is about 135 to 145 mEq/L. This range is the reference for assessing fluid and electrolyte balance because sodium is the main extracellular cation that helps regulate osmotic balance and fluid distribution, with the kidneys and hormones like aldosterone and ADH keeping it within this window. Values below 135 indicate hyponatremia, which can lead to confusion, seizures, or edema in severe cases. Values above 145 indicate hypernatremia, which can cause thirst, confusion, and possible dehydration. Among the options, 125-135 is below normal (hyponatremia), 145-155 is above normal (hypernatremia), and 120-130 is also well below normal, leaving 135-145 as the normal range.