A nurse is reviewing a patient's records and notes that the patient has renal disorder. The nurse expects to note which of the following laboratory results?

Appeared in: JODHPUR AIIMS SNO-2018

Explanation

Creatinine is a waste product generated from normal muscle breakdown.
Healthy kidneys are responsible for filtering creatinine out of the bloodstream and excreting it through urine.
In renal disorders, the glomerular filtration rate (GFR) is reduced, which impairs the kidneys' ability to clear creatinine.
This impaired clearance causes creatinine to accumulate in the blood, resulting in an elevated serum creatinine level, which is a key marker of kidney dysfunction.

Option A: Renal disorders impair the excretion of potassium, leading to its accumulation in the blood, a condition known as hyperkalemia (elevated potassium), not hypokalemia (decreased potassium).
Option B: Kidney failure reduces the excretion of phosphate, causing its level in the blood to rise. This condition is called hyperphosphatemia (elevated phosphate), not hypophosphatemia.
Option D: Chronic renal disorders lead to decreased production of the hormone erythropoietin, which is essential for red blood cell synthesis. This results in normochromic, normocytic anemia, meaning a decreased hemoglobin level.

Clinical Relevance

Nursing practice connection: Use the key finding related to Interpretation of laboratory results in renal disorders to guide bedside assessment, documentation, and the next nursing action.
Monitoring serum creatinine and estimated GFR (eGFR) is fundamental in nursing for tracking the progression of chronic kidney disease (CKD) and assessing for acute kidney injury (AKI).
Nurses must verify a patient's renal function before administering medications that are cleared by the kidneys or are potentially nephrotoxic (e.g., certain antibiotics, NSAIDs, contrast dye) to prevent drug toxicity and further kidney damage.
What if? If the patient's lab results showed a disproportionately high Blood Urea Nitrogen (BUN) compared to creatinine (a high BUN:creatinine ratio), the nurse should suspect a pre-renal cause, such as dehydration or gastrointestinal bleeding, contributing to the kidney dysfunction.

How to Approach the Question

First, identify the core concept of the question, which is the expected laboratory findings in a patient with a 'renal disorder.'
Recall the primary functions of the kidneys: filtering waste products (like creatinine), regulating electrolytes (like potassium and phosphate), and producing hormones (like erythropoietin).
Consider how a 'disorder' would impair these functions. Impaired function means waste products and electrolytes will accumulate in the blood, while hormone production will decrease.
Evaluate each option based on this pathophysiology: An elevated creatinine level is consistent with impaired filtration. Decreased potassium and phosphate are opposite to the expected findings of hyperkalemia and hyperphosphatemia. Increased hemoglobin is opposite to the expected finding of anemia due to low erythropoietin.
By eliminating the incorrect options based on the pathophysiology of renal failure, you can confidently select 'Elevated serum creatinine level' as the correct answer.

Concept Tested & Keywords

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E6 Kaplan Sadock's Synopsis of Psychiatry-2022 (pp 1-3768 of 3768) p. 210-212

E6 Medicine Davidson Principles Practice 24e p. 408-410

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