Which laboratory value would be of greatest concern for a patient in acute renal failure?

In acute renal failure, the primary concern is the kidneys' inability to effectively filter waste products from the blood. Elevated serum creatinine is a direct indicator of kidney function, as creatinine is a waste product of muscle metabolism that is normally excreted by the kidneys. When renal function declines, as seen in acute renal failure, creatinine levels increase significantly due to the accumulation of this waste in the bloodstream.

Monitoring serum creatinine levels allows healthcare professionals to assess the severity of kidney impairment and guide treatment decisions accordingly. Therefore, a significant elevation in serum creatinine is a critical laboratory value that signifies worsening renal function and potential progression of acute renal failure, warranting immediate medical attention and intervention to prevent further complications.

In contrast, while low hemoglobin, increased white blood cell count, and decreased plasma proteins may indicate other health issues, they do not provide direct insight into renal function as effectively as elevated serum creatinine does in this context.