In a patient with a pituitary disorder being treated for fluid balance, which urine finding would indicate improved concentrating ability?

In a patient with a pituitary disorder being treated for fluid balance, which urine finding would indicate improved concentrating ability?

• A. Urine output of 3 liters per day
• B. Urine specific gravity less than 1.025
• C. Urine osmolality of 80 mOsm/kg
• D. Urine pH of 9

Answer: (B)

The main idea is that improving fluid balance from a pituitary disorder should help the kidneys concentrate urine again. When antidiuretic hormone is working, the kidney reabsorbs more water, so the urine becomes more concentrated. Urine concentration is reflected by how dense the urine is, which we assess with urine specific gravity and osmolality. Among the options, a urine specific gravity below 1.025 suggests the urine is not overly dilute and is more concentrated than very dilute urine. The other findings point to ongoing dilute urine (large volume, very low osmolality) or to a factor not related to concentration (pH). So this value best indicates that concentrating ability is improving.

The main idea is that improving fluid balance from a pituitary disorder should help the kidneys concentrate urine again. When antidiuretic hormone is working, the kidney reabsorbs more water, so the urine becomes more concentrated. Urine concentration is reflected by how dense the urine is, which we assess with urine specific gravity and osmolality. Among the options, a urine specific gravity below 1.025 suggests the urine is not overly dilute and is more concentrated than very dilute urine. The other findings point to ongoing dilute urine (large volume, very low osmolality) or to a factor not related to concentration (pH). So this value best indicates that concentrating ability is improving.