What is the most accurate indicator of fluid loss or gain in acutely ill patients?

SIADH is a condition in which your body makes too much antidiuretic hormone (ADH), which controls how your body releases and conserves water.

SIADH makes it harder for your kidneys to release water and causes the levels of electrolytes, like sodium, to fall due to water retention.

This leads to hyponatremia, which is when you have low levels of sodium in your blood.

Choice B is wrong because hypernatremia is when you have high levels of sodium in your blood.

This can occur due to dehydration, excessive salt intake, or kidney problems.

Choice C is wrong because hyperkalemia is when you have high levels of potassium in your blood.

This can occur due to kidney failure, acidosis, or certain medications.

Choice D is wrong because hypokalemia is when you have low levels of potassium in your blood.

This can occur due to vomiting, diarrhea, diuretics, or alkalosis.

Clearance = urine flow rate x urine concentration / plasma concentration. This is the formula for calculating the renal clearance of a substance that is neither reabsorbed nor secreted by the tubules. Renal clearance is the volume of plasma that would have to be filtered by the glomeruli each minute to account for the amount of that substance appearing in the urine each minute.

Choice B is wrong because it has the urine concentration and plasma concentration inverted.

This would give an incorrect value for renal clearance.

Choice C is wrong because it has the plasma flow rate instead of the urine flow rate.

Plasma flow rate is not directly related to renal clearance.

Choice D is wrong because it has both the plasma flow rate and the urine concentration and plasma concentration inverted.

This would give an incorrect value for renal clearance.

Normal ranges for renal clearance vary depending on the substance, age, sex, and body size.

For example, the normal range for creatinine clearance is 85-125 mL/min for males and 75-115 mL/min for females.