200+ Free CNN Practice Questions

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Question 1

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Which of the following is the most common cause of acute kidney injury (AKI) in hospitalized patients?

Glomerulonephritis

Prerenal azotemia

Acute tubular necrosis

Obstructive uropathy

to track

2026 Statistics

Key Facts: CNN Exam

150

Exam Questions

NNCC

70%

Passing Score

Scaled score 95

3 hrs

Exam Duration

NNCC

$350

Exam Fee

NNCC

45%

Hemodialysis

Largest section

3 years

Certification Validity

NNCC

The CNN exam has 150 questions in 3 hours with a passing score of 70% (scaled score 95). The five content areas are: Renal Disease and Pathophysiology (20%), Hemodialysis (45%), Peritoneal Dialysis (15%), Transplantation and Home Therapies (10%), and Professional Issues (10%). Requires RN license and 2,000+ hours nephrology experience. Certification valid for 3 years. Exam fee is $350.

Sample CNN Practice Questions

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1Which of the following is the most common cause of acute kidney injury (AKI) in hospitalized patients?

A.Glomerulonephritis

B.Prerenal azotemia

C.Acute tubular necrosis

D.Obstructive uropathy

Explanation: Acute tubular necrosis (ATN) is the most common cause of AKI in hospitalized patients, accounting for approximately 45% of cases. ATN results from ischemia (often due to prolonged prerenal azotemia) or nephrotoxic injury. While prerenal azotemia is common, it is reversible if corrected promptly and does not cause structural kidney damage unless prolonged.

2A patient with CKD stage 4 has an eGFR of 28 mL/min/1.73m². What is the recommended protein intake for this patient?

A.1.2-1.5 g/kg/day

B.0.8-1.0 g/kg/day

C.0.6-0.8 g/kg/day

D.0.3-0.5 g/kg/day

Explanation: For CKD stages 3-5 (non-dialysis), the recommended protein intake is 0.6-0.8 g/kg/day to reduce uremic symptoms and slow progression. Higher protein intake (1.2-1.5 g/kg/day) is recommended for dialysis patients to compensate for losses. Very low protein diets (0.3-0.5 g/kg/day) are not routinely recommended due to risk of malnutrition.

3Which electrolyte imbalance is most commonly associated with tumor lysis syndrome?

A.Hypokalemia, hypophosphatemia, hypouricemia

B.Hyperkalemia, hyperphosphatemia, hyperuricemia

C.Hyponatremia, hypocalcemia, hypomagnesemia

D.Hypernatremia, hypercalcemia, hypermagnesemia

Explanation: Tumor lysis syndrome is characterized by hyperkalemia, hyperphosphatemia, and hyperuricemia due to the rapid release of intracellular contents from dying tumor cells. The hyperphosphatemia causes secondary hypocalcemia due to calcium-phosphate precipitation. This metabolic emergency requires immediate intervention to prevent cardiac arrhythmias and acute kidney injury.

4A patient presents with nephrotic syndrome. Which of the following laboratory findings is most characteristic?

A.Hematuria with dysmorphic red blood cells

B.Proteinuria >3.5 g/day with hypoalbuminemia

C.RBC casts and elevated creatinine

D.Sterile pyuria and eosinophiluria

Explanation: Nephrotic syndrome is characterized by proteinuria >3.5 g/day, hypoalbuminemia (<3.0 g/dL), edema, and hyperlipidemia. Hematuria with dysmorphic RBCs and RBC casts are features of nephritic syndrome. Sterile pyuria and eosinophiluria suggest interstitial nephritis, often drug-induced.

5Which medication class is contraindicated in patients with bilateral renal artery stenosis?

A.Beta-blockers

B.ACE inhibitors or ARBs

C.Calcium channel blockers

D.Loop diuretics

Explanation: ACE inhibitors and ARBs are contraindicated in bilateral renal artery stenosis because they block angiotensin II-mediated efferent arteriolar constriction in the glomerulus. This reduces the pressure gradient across the glomerulus and can precipitate acute kidney injury. Calcium channel blockers are preferred in this population as they preserve glomerular filtration rate.

6A 45-year-old patient with autosomal dominant polycystic kidney disease (ADPKD) asks about the most common cause of death in this condition. What is the correct answer?

A.Infection from infected cysts

B.Cardiovascular disease

C.Intracranial hemorrhage from aneurysm rupture

D.Progressive renal failure

Explanation: While ADPKD commonly leads to end-stage renal disease, cardiovascular disease is the most common cause of death in these patients. Hypertension is common and often develops early. Intracranial aneurysms occur in 5-10% of patients but are not the leading cause of mortality. Early blood pressure control is crucial to reduce cardiovascular risk and slow disease progression.

7Which of the following is the primary target for phosphate binding in patients with CKD-MBD?

A.Parathyroid hormone (PTH)

B.25-hydroxyvitamin D

C.1,25-dihydroxyvitamin D

D.Dietary phosphate absorption

Explanation: Phosphate binders work primarily by binding dietary phosphate in the gastrointestinal tract, reducing its absorption. They do not directly affect PTH or vitamin D levels, though controlling phosphate helps manage secondary hyperparathyroidism. Common binders include calcium-based binders (calcium acetate, calcium carbonate) and non-calcium-based binders (sevelamer, lanthanum).

8A patient with diabetic nephropathy has an albumin-to-creatinine ratio (ACR) of 450 mg/g. How should this be classified?

A.Normal to mildly increased (A1)

B.Moderately increased (A2)

C.Severely increased (A3)

D.Nephrotic range proteinuria

Explanation: Albuminuria categories are: A1 (<30 mg/g or <3 mg/mmol), A2 (30-300 mg/g or 3-30 mg/mmol), and A3 (>300 mg/g or >30 mg/mmol). An ACR of 450 mg/g indicates severely increased albuminuria (A3), which carries a high risk for CKD progression and cardiovascular events. Nephrotic range proteinuria is defined as >3.5 g/day of total protein, not albumin.

9Which of the following is most suggestive of acute interstitial nephritis (AIN)?

A.Nephrotic range proteinuria and edema

B.Hematuria with RBC casts and hypertension

C.Recent antibiotic use, fever, rash, and eosinophiluria

D.Hyperkalemia and metabolic alkalosis

Explanation: AIN is commonly drug-induced (especially antibiotics, NSAIDs, proton pump inhibitors). The classic triad of fever, rash, and eosinophilia/eosinophiluria occurs in less than 10% of cases, but these features together with recent medication use strongly suggest AIN. Nephrotic syndrome suggests glomerular disease, while hematuria with RBC casts suggests glomerulonephritis.

10A patient with CKD stage 5 has a serum potassium of 6.8 mEq/L and ECG showing peaked T waves. Which is the first-line treatment to stabilize the cardiac membrane?

A.Sodium polystyrene sulfonate (Kayexalate)

B.Intravenous calcium gluconate

C.Intravenous regular insulin with dextrose

D.Sodium bicarbonate

Explanation: IV calcium gluconate is the first-line treatment to stabilize cardiac membranes in hyperkalemia with ECG changes. It works within minutes but its effect lasts only 30-60 minutes. Other treatments (insulin/glucose, beta-agonists, bicarbonate) shift potassium intracellularly, while binders (Kayexalate, patiromer) remove potassium from the body but work more slowly.

About the CNN Exam

The CNN (Certified Nephrology Nurse) exam validates expertise in nephrology nursing care. It covers renal disease pathophysiology, hemodialysis, peritoneal dialysis, transplantation and home therapies, and professional issues. The exam tests knowledge of acute and chronic kidney disease, dialysis principles, vascular access, complications management, and patient education.

Questions

150 scored questions

Time Limit

3 hours

Passing Score

70% (Scaled score 95)

Exam Fee

$350 (NNCC (Nephrology Nursing Certification Commission))

CNN Exam Content Outline

45%

Hemodialysis

Dialysis principles, vascular access, machine operation, treatment delivery, complications management, patient assessment, water treatment, and dialyzer reuse

20%

Renal Disease and Pathophysiology

Acute kidney injury, chronic kidney disease, end-stage renal disease, electrolyte imbalances, acid-base disorders, anemia management, and bone disease

15%

Peritoneal Dialysis

PD modalities, catheter care, infection control, complications, and patient education

10%

Transplantation and Home Therapies

Transplant evaluation, immunosuppression, complications, home hemodialysis, and nocturnal dialysis

10%

Professional Issues

Patient education, ethics, legal issues, quality improvement, infection control standards, and regulatory requirements

How to Pass the CNN Exam

What You Need to Know

Passing score: 70% (Scaled score 95)
Exam length: 150 questions
Time limit: 3 hours
Exam fee: $350

Keys to Passing

Complete 500+ practice questions
Score 80%+ consistently before scheduling
Focus on highest-weighted sections
Use our AI tutor for tough concepts

CNN Study Tips from Top Performers

1Master hemodialysis (45%) — dialysis principles, vascular access types, and complications management

2Study renal pathophysiology — AKI, CKD stages, ESRD progression, and disease processes

3Know electrolyte imbalances — hyperkalemia, hyperphosphatemia, and management strategies

4Understand vascular access — AV fistula (preferred), AV graft, central venous catheters

5Review peritoneal dialysis — CAPD vs APD, catheter care, peritonitis prevention and treatment

6Learn transplant basics — immunosuppressants (tacrolimus, mycophenolate), rejection types, infection prevention

Frequently Asked Questions

What is the CNN certification?

CNN (Certified Nephrology Nurse) is a certification from the NNCC for registered nurses specializing in nephrology. It validates expertise in renal disease management, hemodialysis, peritoneal dialysis, transplantation, and professional nursing issues in dialysis settings.

How many questions are on the CNN exam?

The CNN exam has 150 multiple-choice questions with a 3-hour time limit. The passing score is 70% (scaled score of 95). Hemodialysis is the largest content area at 45% of the exam.

What are the prerequisites for the CNN exam?

You need an active RN license, at least 2,000 hours of nephrology nursing experience, and 30 hours of continuing education in nephrology within the last 3 years. Experience must be within the last 2 years.

What is the most heavily tested topic on the CNN exam?

Hemodialysis accounts for 45% of the exam — nearly half of all questions. Focus on dialysis principles, vascular access (AVF, AVG, catheters), machine operation, complications (hypotension, cramping, air embolism), and water treatment.

How should I prepare for the CNN exam?

Plan for 150-200 hours of study. Master hemodialysis principles (45% of exam). Study renal pathophysiology, electrolyte management, and acid-base disorders. Know peritoneal dialysis modalities and complications. Understand transplant immunosuppression basics. Complete 200+ practice questions with detailed explanations.