CNN Exam Flashcards

Q: What is the passing score for the CNN exam?

The passing standard is a scaled score of 95, which requires answering approximately 70% of the questions correctly. The NNCC uses scaled scores to ensure fairness across different test versions.

Q: What are the eligibility requirements to take the CNN exam?

To take the CNN exam, you must hold a full and unrestricted RN license in the U.S. or its territories, have at least 2,500 hours of nephrology nursing experience within the 2 years before applying, and complete 30 contact hours of approved nephrology continuing education within that same 2-year period. NNCC's role-based update (effective Summer 2026) removed the previous baccalaureate (BSN) degree requirement.

Q: What is the difference between CNN and CDN certification?

Both NNCC credentials are now role-based with no degree requirement. The CNN (Certified Nephrology Nurse) covers the full scope of nephrology nursing and requires 2,500 hours of nephrology experience across settings (home dialysis, acute kidney injury, critical care, CKD management, transplant) within 2 years. The CDN (Certified Dialysis Nurse) focuses on in-center hemodialysis and also requires 2,500 hours within 2 years caring for or supervising in-center hemodialysis patients.

Q: What is the content breakdown of the CNN exam?

Under the current NNCC blueprint, the CNN exam content areas are: Concepts of Kidney Disease (approximately 38%), Hemodialysis (approximately 30%), Peritoneal Dialysis (approximately 22%), Transplant (approximately 5%), and Acute Therapies (approximately 5%). A revised blueprint takes effect September 1, 2026 (Concepts of Kidney Disease 30%, Acute Inpatient Therapies 25%, Peritoneal Dialysis 20%, Home Hemodialysis 15%, Transplant 10%).

Q: How long is the CNN certification valid?

The CNN certification is valid for 3 years (effective from the last day of the month in which you passed). To recertify, you must hold a full, unrestricted RN license, have at least 1,500 hours of nephrology nursing experience during the 3-year cycle, and complete 45 contact hours of approved continuing education (at least 15 of them nephrology-specific) — or recertify by retaking the exam, which waives the continuing-education requirement.

Question 1

What is the educational requirement for the CNN exam?

Accepted Answer

There is no degree requirement. NNCC's role-based update (effective Summer 2026) removed the former baccalaureate (BSN) requirement; you only need a full, unrestricted RN license plus the required nephrology experience and continuing education. Both CNN and CDN are now open to all RNs regardless of degree.

Question 2

How many hours of nephrology nursing experience are required for the CNN exam?

Accepted Answer

At least 2,500 hours of nephrology nursing practice as an RN within the 2 years prior to application (in areas such as home dialysis, acute kidney injury, critical care, CKD management, or kidney transplant).

Question 3

How long is the CNN credential valid, and what is required for recertification?

Accepted Answer

The CNN certification is valid for 3 years. Recertification requires a full, unrestricted RN license, at least 1,500 hours of nephrology experience during the cycle, and 45 contact hours of continuing education (minimum 15 nephrology-specific) — or passing the exam again, which waives the CE requirement.

Question 4

What is the question count, time limit, and passing score of the CNN exam?

Accepted Answer

The exam consists of 150 multiple-choice questions with a 3-hour time limit. The passing standard is a scaled score of 95 (corresponding to approximately 70% correct).

Question 5

Which clinical area represents the largest percentage of the current CNN exam blueprint?

Accepted Answer

Concepts of Kidney Disease is the largest area at approximately 38%, followed by Hemodialysis (~30%), Peritoneal Dialysis (~22%), Transplant (~5%), and Acute Therapies (~5%). A revised blueprint effective September 1, 2026 reweights these to Concepts of Kidney Disease 30%, Acute Inpatient Therapies 25%, Peritoneal Dialysis 20%, Home Hemodialysis 15%, and Transplant 10%.

Question 6

Where is erythropoietin (EPO) produced in the kidneys, and what is its role?

Accepted Answer

EPO is produced by peritubular interstitial cells in the renal cortex. It stimulates the bone marrow to produce red blood cells. In CKD, destruction of these cells leads to anemia.

Question 7

How does the fractional excretion of sodium (FENa) help distinguish prerenal azotemia from acute tubular necrosis (ATN)?

Accepted Answer

A FENa < 1% indicates prerenal azotemia (kidneys conserve sodium due to hypoperfusion). A FENa > 2% indicates ATN (tubular damage impairs sodium reabsorption, causing sodium loss in urine).

Question 8

What GFR ranges define Chronic Kidney Disease (CKD) Stages 3a, 3b, 4, and 5?

Accepted Answer

Stage 3a: GFR 45–59 mL/min; Stage 3b: GFR 30–44 mL/min; Stage 4: GFR 15–29 mL/min (severe reduction); Stage 5: GFR < 15 mL/min (kidney failure, dialysis indication).

Question 9

What is the classic tetrad of clinical findings that defines nephrotic syndrome?

Accepted Answer

1) Severe proteinuria (> 3.5 g/24h), 2) Hypoalbuminemia (< 3.0 g/dL), 3) Generalized edema, and 4) Hyperlipidemia. It results from increased glomerular permeability.

Question 10

Why does chronic kidney disease lead to secondary hyperparathyroidism and bone disease (CKD-MBD)?

Accepted Answer

Kidneys fail to excrete phosphorus and cannot convert vitamin D to its active form (calcitriol). Hypocalcemia and hyperphosphatemia result, stimulating parathyroid hormone (PTH) release, which resorbs calcium from bone.

Question 11

What ECG changes progress as serum potassium levels rise, and what is the immediate stabilizer?

Accepted Answer

Peaked T waves appear first, followed by PR prolongation, QRS widening, and loss of P waves. IV Calcium Gluconate must be given immediately to stabilize the cardiac cell membrane.

Question 12

Why are ACE inhibitors and ARBs contraindicated in bilateral renal artery stenosis?

Accepted Answer

They block angiotensin II, preventing efferent arteriolar constriction, which is necessary to maintain glomerular filtration pressure when renal perfusion is compromised. This can precipitate acute kidney injury (AKI).

Question 13

What are the three categories of albuminuria based on the Urine Albumin-to-Creatinine Ratio (ACR)?

Accepted Answer

Category A1 (Normal/mild): < 30 mg/g; Category A2 (Moderate): 30–300 mg/g; Category A3 (Severe): > 300 mg/g. Severe albuminuria is a key predictor of CKD progression.

Question 14

What are the common causes and classic clinical triad of acute interstitial nephritis (AIN)?

Accepted Answer

AIN is usually drug-induced (NSAIDs, antibiotics, PPIs) causing immune-mediated tubulointerstitial inflammation. The classic triad is fever, rash, and arthralgia (often with eosinophiluria).

Question 15

What central nervous, gastrointestinal, and dermatologic signs indicate severe uremia in advanced CKD?

Accepted Answer

Asterixis (flapping tremor), encephalopathy/confusion, metallic taste, nausea/vomiting, anorexia, pericarditis, and uremic frost on the skin. These indicate urgent need for renal replacement therapy.

Question 16

What is the primary physical mechanism of solute removal during hemodialysis, and what factors optimize it?

Accepted Answer

Diffusion, which is the movement of solutes down a concentration gradient from blood to dialysate. It is optimized by maximizing concentration gradients, countercurrent flow, and dialyzer surface area.

Question 17

How is fluid removed during hemodialysis (ultrafiltration)?

Accepted Answer

Fluid is removed by convection/ultrafiltration, which is driven by a hydrostatic pressure gradient (transmembrane pressure, TMP) created by the dialysis machine across the semipermeable membrane.

Question 18

What are the minimum KDOQI adequacy targets for spKt/V and URR in thrice-weekly hemodialysis?

Accepted Answer

Single-pool Kt/V (spKt/V) target is ≥ 1.4 per session (minimum delivered 1.2). The Urea Reduction Ratio (URR) target is ≥ 70% (minimum delivered 65%).

Question 19

Why is an arteriovenous fistula (AVF) the preferred access, and how long does it take to mature?

Accepted Answer

An AVF uses native vessels, offering the lowest infection and thrombosis rates. It takes 6–12 weeks to mature (vein wall thickens and dilates to handle high blood flow).

Question 20

What physical assessment findings confirm patency of an AV fistula or graft?

Accepted Answer

A palpable thrill (continuous vibration) and an audible bruit (low-pitched, continuous rushing sound). A high-pitched, systolic-only bruit suggests stenosis; absence of both indicates thrombosis.

Question 21

What causes Dialysis Disequilibrium Syndrome (DDS), and how is it prevented in new patients?

Accepted Answer

Rapid clearance of urea decreases blood osmolality, causing water to shift into brain cells, leading to cerebral edema. It is prevented by limiting solute clearance during initial treatments (lower Qb, shorter time).

Question 22

What are the priority nursing interventions for a patient experiencing symptomatic intradialytic hypotension?

Accepted Answer

Place patient in Trendelenburg position (unless contraindicated), reduce or stop ultrafiltration (UF), administer a normal saline bolus (100–250 mL) as prescribed, and check vitals.

Question 23

What is vascular access steal syndrome, and what are the key clinical signs?

Accepted Answer

It occurs when blood flow is diverted from the distal extremity into the low-resistance access. Signs include coldness, pain, paresthesias, pallor, and weak distal pulses in the access limb.

Question 24

What is the maximum allowable chloramine concentration in dialysis water, and what occurs if it is exceeded?

Accepted Answer

The AAMI limit is < 0.1 mg/L (or 0.1 ppm). Excess chloramines pass through the dialyzer membrane, causing hemolysis (rupturing red blood cells) and methemoglobinemia.

Question 25

What is the function of the carbon tanks in a dialysis water system, and how are they monitored?

Accepted Answer

Carbon tanks remove chlorine and chloramines through adsorption. Dialysis systems require two tanks in series. Chloramine testing must be performed before the first patient shift and every 4 hours from the sample port between the tanks.

Question 26

What is the difference between Type A and Type B dialyzer reactions (First Use Syndrome)?

Accepted Answer

Type A is an immediate, IgE-mediated hypersensitivity reaction (usually to ethylene oxide sterilant) causing dyspnea, hives, and anaphylaxis. Type B is a milder, complement-activated reaction causing chest and back pain 20–40 minutes into treatment.

Question 27

What patient conditions absolutely contraindicate the reuse of hemodialyzers?

Accepted Answer

Active hepatitis B infection (due to high transmission risk), positive HIV or hepatitis C status (per facility policy to prevent cross-contamination), and systemic infections/sepsis.

Question 28

What is the difference between the 'rope ladder' and 'buttonhole' cannulation techniques?

Accepted Answer

Rope ladder rotates needle sites along the length of the access to prevent aneurysm formation. Buttonhole uses constant sites and angles to create a mature tract, suitable for self-cannulation, but has a higher infection risk.

Question 29

What is the emergency positioning for a patient with a suspected venous air embolism, and why?

Accepted Answer

Place the patient in left lateral Trendelenburg (Durant's Maneuver). This traps the air bolus in the apex of the right ventricle, preventing it from entering the pulmonary artery and blocking outflow.

Question 30

What defines a high-flux dialyzer membrane compared to a low-flux membrane?

Accepted Answer

High-flux membranes have larger pores and higher ultrafiltration coefficients (KUF). They allow clearance of larger 'middle molecules' (e.g., beta-2 microglobulin) and faster fluid removal.

Question 31

What is the primary osmotic agent in standard peritoneal dialysis dialysate, and what are its standard concentrations?

Accepted Answer

Dextrose (glucose monohydrate) is the osmotic agent, available in 1.5%, 2.5%, and 4.25% concentrations. Higher concentrations create a larger osmotic gradient, increasing fluid removal (ultrafiltration).

Question 32

What is the difference between CAPD and APD?

Accepted Answer

Continuous Ambulatory Peritoneal Dialysis (CAPD) is manual, with 4–5 exchanges during waking hours and long overnight dwells. Automated Peritoneal Dialysis (APD) uses a cycler machine to perform multiple exchanges overnight, leaving the day clear.

Question 33

What diagnostic findings in peritoneal fluid confirm a diagnosis of PD-related peritonitis?

Accepted Answer

Cloudy dialysate effluent with a white blood cell count > 100/mcL (with at least 50% polymorphonuclear neutrophils), clinical symptoms (abdominal pain, rebound tenderness), and/or positive Gram stain/culture.

Question 34

What is a Peritoneal Equilibration Test (PET) and how does it guide PD prescriptions?

Accepted Answer

A PET measures the rate of solute transfer (creatinine and glucose) across the peritoneal membrane. It classifies patients as high, high-average, low-average, or low transporters. High transporters need shorter, faster dwells (like APD); low transporters need longer dwells (like CAPD).

Question 35

What symptoms distinguish a PD catheter tunnel infection from a simple exit-site infection?

Accepted Answer

Exit-site infection shows redness and purulence at the external opening. Tunnel infection shows pain, swelling, tenderness, and erythema along the subcutaneous pathway of the catheter, carrying a high risk of peritonitis and requiring systemic antibiotics.

Question 36

What causes fibrin formation in PD effluent, and how is it managed?

Accepted Answer

Fibrin appears as white, gelatinous shreds in the effluent, often stimulated by peritoneal inflammation or peritonitis. It can block the catheter. It is treated by adding heparin (e.g., 500–1000 units/L) to the dialysate bags as prescribed.

Question 37

Why is constipation a frequent cause of poor PD dialysate inflow or drainage, and what is the management?

Accepted Answer

Distended bowel loops compress the peritoneal catheter and alter its position. Management includes stool softeners and daily bowel regimens (avoiding phosphorus/magnesium-containing laxatives).

Question 38

What is Encapsulating Peritoneal Sclerosis (EPS) and what are its symptoms?

Accepted Answer

EPS is a rare, severe complication where the peritoneal membrane becomes thickened and fibrotic, leading to bowel obstruction. Symptoms include persistent nausea, vomiting, malnutrition, and ascites. It often requires stopping PD.

Question 39

What is the priority nursing care for a newly placed PD catheter during the postoperative healing phase?

Accepted Answer

Maintain sterile dressings, avoid catheter manipulation, perform flush-only exchanges as ordered to prevent fibrin occlusion, and delay routine dialysis use for at least 10–14 days to allow healing and prevent leaks.

Question 40

What is the minimum weekly Kt/V target for adequacy in peritoneal dialysis patients?

Accepted Answer

The KDOQI guideline recommends a minimum total (peritoneal + residual renal) weekly Kt/V of 1.7. This requires a 24-hour urine and dialysate collection.

Question 41

What is the standard triple-drug immunosuppressive regimen for a kidney transplant recipient?

Accepted Answer

1) A calcineurin inhibitor (CNI: Tacrolimus or Cyclosporine), 2) An antimetabolite (Mycophenolate Mofetil or Azathioprine), and 3) A corticosteroid (Prednisone).

Question 42

What is a major adverse effect of calcineurin inhibitors (tacrolimus/cyclosporine) on the kidneys, and how is it monitored?

Accepted Answer

Nephrotoxicity. CNIs cause vasoconstriction of the afferent arterioles, reducing GFR and raising creatinine. Levels must be monitored via periodic trough blood levels (taken just before the next dose).

Question 43

How do hyperacute, acute, and chronic kidney transplant rejections differ in timing and mechanism?

Accepted Answer

Hyperacute occurs within minutes/hours (pre-existing antibodies; requires immediate graft removal). Acute occurs weeks/months post-transplant (T-cell mediated; treatable with high-dose steroids/thymoglobulin). Chronic occurs over years (progressive fibrosis; untreatable, leads to graft loss).

Question 44

What water testing responsibility is unique to home hemodialysis (HHD) patients?

Accepted Answer

HHD patients must test their home water system for chlorine/chloramines prior to every treatment session and perform periodic bacterial/endotoxin cultures of the product water.

Question 45

What is the most common viral opportunistic infection in kidney transplant recipients, and when does it typically occur?

Accepted Answer

Cytomegalovirus (CMV). It typically occurs 1–6 months post-transplant (when immunosuppression is highest). Symptoms include fever, leukopenia, and organ-specific disease (pneumonitis, colitis). Prevented with valganciclovir.

Question 46

What are the CMS Conditions for Coverage (CfC) for End-Stage Renal Disease (ESRD) facilities?

Accepted Answer

Federal regulations that dialysis facilities must meet to receive Medicare reimbursement. They mandate patient rights, water quality standards, reuse safety, interdisciplinary plans of care, and quality assessment/performance improvement (QAPI) programs.

Question 47

What is the primary focus of the Quality Assessment and Performance Improvement (QAPI) program in a dialysis unit?

Accepted Answer

Systematically tracking clinical outcomes (adequacy, anemia, bone disease, vascular access, infections) to identify gaps, implement corrective plans (clinical audits), and improve patient safety and care processes.

Question 48

What is the nurse's role when an ESRD patient expresses the desire to withdraw from dialysis treatment?

Accepted Answer

Support patient autonomy, assess for depression/cognitive issues, ensure the patient understands the consequences of withdrawal, facilitate interdisciplinary support (palliative care/social work), and document the decision.

Question 49

How often must the interdisciplinary team review and update a hemodialysis patient's plan of care?

Accepted Answer

Initially within 30 days or 13 treatments of admission, then stable patients are reviewed annually. Unstable patients (e.g., frequent hospitalizations, inadequate dialysis) must be reviewed monthly.

Question 50

Why is CRRT preferred over intermittent hemodialysis for critically ill patients with acute kidney injury?

Accepted Answer

CRRT runs continuously at lower blood/fluid flow rates, allowing slow, gentle solute and fluid removal. This prevents the rapid hemodynamic shifts and hypotension associated with intermittent HD in unstable patients.

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