What does a urine sodium level greater than 20 suggest?

A urine sodium level greater than 20 mEq/L typically suggests renal salt wasting. This indicates that the kidneys are excreting sodium despite possible physiological needs for sodium retention. In conditions such as heart failure, cirrhosis, or nephrotic syndrome where the body may need to retain sodium for fluid balance, a urine sodium level above this threshold points to an inability of the kidneys to retain sodium properly.

This finding can help healthcare providers distinguish between various causes of fluid imbalance. For instance, in cases of renal tubular dysfunction or certain types of acute kidney injury, one might also see elevated urine sodium levels, indicating that the kidneys are not functioning optimally in terms of sodium reabsorption.

Understanding the implications of urine sodium levels is essential for managing conditions that can affect fluid and electrolyte balance. A urine sodium level greater than 20 is a key indicator that the kidneys are actually wasting sodium rather than retaining it, which can guide further diagnostic and therapeutic decisions.