In a patient with normal kidney function and hyponatremia, this test is not the highest yield for an initial test. Try again!

Well done – orthostatics are a sensitive way to assess a patient’s volume status. This patient’s blood pressure drops to 100/60 with a HR of 90 upon standing (after standing for 2-3 minutes).

In a patient with normal kidney function and hyponatremia, this test is not the highest yield for an initial test. Try again!

Excellent! Urine osmolality can help us understand the etiology of a patient’s hyponatremia and tell us about the activity of the antidiuretic hormone (ADH). Higher osmolality suggests ADH activity is high, while lower osmolality suggests lower activity of ADH. This patient’s urine osmolality is 744 mOsm/kg.

Excellent! Urine sodium can help us understand what the effective circulating volume or effective arterial volume (EAV) of a patient is. This patient’s urine sodium is 53 meq/L.

In a patient with normal kidney function and hyponatremia, this is not the highest yield initial test.

Though psuedohyponatremia is not common, this test can help us ensure that our patient’s hyponatremia is true hyponatremia. The serum osmolality is 268 mOsm/kg. (normal range: 275 – 295 mOsm/kg)