Which laboratory result would be of most concern for a patient with chronic renal failure?

Which laboratory result would be of most concern for a patient with chronic renal failure?

• A. Potassium: 7 mmol/L
• B. pH: 7.37
• C. Sodium: 142 mmol/L
• D. Blood Urea Nitrogen (BUN): 6.8 mmol/L

Answer: (A)

In chronic kidney disease, the kidneys lose their ability to excrete potassium effectively, so potassium can accumulate in the blood. A potassium level of 7 mmol/L is significantly higher than the normal range (about 3.5–5.0). This level can seriously affect the heart's electrical activity, leading to dangerous changes on the ECG and increasing the risk of life-threatening arrhythmias or cardiac arrest if not treated promptly. The other values here don’t indicate the same immediate threat. A pH of 7.37 is within the normal range, though CKD can cause metabolic acidosis over time. Sodium at 142 is normal, and the BUN value shown (6.8 mmol/L) is not elevated relative to what’s typically seen in CKD, where BUN is often higher. Thus, the hyperkalemia represents the most urgent concern for a patient with chronic renal failure.

In chronic kidney disease, the kidneys lose their ability to excrete potassium effectively, so potassium can accumulate in the blood. A potassium level of 7 mmol/L is significantly higher than the normal range (about 3.5–5.0). This level can seriously affect the heart's electrical activity, leading to dangerous changes on the ECG and increasing the risk of life-threatening arrhythmias or cardiac arrest if not treated promptly.

The other values here don’t indicate the same immediate threat. A pH of 7.37 is within the normal range, though CKD can cause metabolic acidosis over time. Sodium at 142 is normal, and the BUN value shown (6.8 mmol/L) is not elevated relative to what’s typically seen in CKD, where BUN is often higher. Thus, the hyperkalemia represents the most urgent concern for a patient with chronic renal failure.