Elevation in which laboratory value is associated with renal failure, chronic nephritis, or urinary obstruction?

Elevation in which laboratory value is associated with renal failure, chronic nephritis, or urinary obstruction?

• A. Creatinine
• B. Hemoglobin
• C. Sodium
• D. Potassium

Answer: (A)

Creatinine rises when kidney function declines because it is a waste product cleared almost entirely by the kidneys. When filtration is reduced—as in renal failure, chronic nephritis, or urinary obstruction—creatinine is not cleared efficiently and builds up in the blood, making it a direct and reliable indicator of impaired renal function. Sodium and hemoglobin aren’t as consistently tied to these specific kidney conditions: sodium levels can fluctuate with fluid status, potassium may rise in advanced failure but isn’t as specifically linked to obstruction or nephritis, and hemoglobin reflects overall blood health rather than filtration capacity. This is why creatinine is the best sign among common labs for these kidney problems.

Creatinine rises when kidney function declines because it is a waste product cleared almost entirely by the kidneys. When filtration is reduced—as in renal failure, chronic nephritis, or urinary obstruction—creatinine is not cleared efficiently and builds up in the blood, making it a direct and reliable indicator of impaired renal function. Sodium and hemoglobin aren’t as consistently tied to these specific kidney conditions: sodium levels can fluctuate with fluid status, potassium may rise in advanced failure but isn’t as specifically linked to obstruction or nephritis, and hemoglobin reflects overall blood health rather than filtration capacity. This is why creatinine is the best sign among common labs for these kidney problems.