CERTIFIED DIALYSIS NURSE (CDN) EXAM
Questions and Answers| Latest Update| Pass Guaranteed
Comprehensive Review Covering Renal Physiology, Hemodialysis, Vascular Access,
Peritoneal Dialysis, Complications, Medications, Nutrition, Safety, and Psychosocial Care
Q1. What is the functional unit of the kidney?
A. Glomerulus
B. Nephron
C. Bowman's capsule
D. Loop of Henle
Answer: B
Rationale: The nephron is the basic structural and functional unit of the kidney. Each
kidney contains approximately one million nephrons, each consisting of a glomerulus,
Bowman's capsule, proximal tubule, loop of Henle, distal tubule, and collecting duct.
Q2. Which hormone is produced by the kidneys to stimulate red blood cell production?
A. Renin
B. Aldosterone
C. Erythropoietin
D. Calcitriol
Answer: C
Rationale: Erythropoietin (EPO) is produced by peritubular fibroblasts in the kidney in
response to hypoxia. It stimulates the bone marrow to produce red blood cells. In chronic
kidney disease, EPO production declines, leading to anemia.
Q3. Which structure is responsible for the final concentration of urine?
A. Proximal convoluted tubule
B. Loop of Henle
C. Collecting duct
D. Glomerulus
Answer: C
Rationale: The collecting duct, under the influence of antidiuretic hormone (ADH), is
responsible for the final concentration of urine by regulating water reabsorption.
Q4. Normal glomerular filtration rate (GFR) in a healthy adult is approximately:
A. 10-20 mL/min
, B. 60-70 mL/min
C. 90-120 mL/min
D. 150-180 mL/min
Answer: C
Rationale: Normal GFR in a healthy adult is approximately 90-120 mL/min/1.73m². A
GFR below 15 mL/min generally indicates kidney failure (Stage 5 CKD) requiring renal
replacement therapy.
Q5. The renin-angiotensin-aldosterone system (RAAS) primarily functions to regulate:
A. Red blood cell production
B. Blood pressure and fluid balance
C. Calcium and phosphorus balance
D. Vitamin D activation
Answer: B
Rationale: The RAAS regulates blood pressure and fluid/electrolyte balance. Renin is
released in response to low blood pressure or low sodium, ultimately leading to
angiotensin II formation and aldosterone release, which increases sodium and water
retention.
Q6. Which electrolyte is primarily regulated by aldosterone in the distal tubule?
A. Calcium
B. Sodium
C. Phosphorus
D. Magnesium
Answer: B
Rationale: Aldosterone acts on the distal convoluted tubule and collecting duct to
increase sodium reabsorption in exchange for potassium and hydrogen ion excretion.
Q7. The kidneys help maintain acid-base balance primarily by:
A. Excreting excess glucose
B. Reabsorbing bicarbonate and excreting hydrogen ions
C. Producing insulin
D. Filtering large proteins
Answer: B
,Rationale: The kidneys maintain acid-base balance by reabsorbing filtered bicarbonate
and excreting hydrogen ions as titratable acid and ammonium. This is a key function lost
in kidney failure, resulting in metabolic acidosis.
Q8. Which of the following best describes the process of diffusion in dialysis?
A. Movement of water across a semipermeable membrane due to a pressure
gradient
B. Movement of solutes from an area of higher concentration to lower concentration
C. Movement of solutes against a concentration gradient using energy
D. Movement of plasma proteins across the membrane
Answer: B
Rationale: Diffusion is the movement of solutes from an area of higher concentration to
an area of lower concentration across a semipermeable membrane. This is the primary
mechanism for solute removal in hemodialysis.
Q9. Ultrafiltration in hemodialysis refers to:
A. Removal of solutes by diffusion
B. Removal of fluid by a pressure gradient across the membrane
C. Removal of red blood cells
D. The process of clotting prevention
Answer: B
Rationale: Ultrafiltration is the removal of plasma water (fluid) across a semipermeable
membrane driven by a hydrostatic or osmotic pressure gradient (transmembrane
pressure).
Q10. Which lab value best reflects long-term kidney function over the previous 24
hours of urine collection?
A. Serum creatinine
B. Creatinine clearance
C. BUN
D. Serum potassium
Answer: B
Rationale: Creatinine clearance, calculated from a 24-hour urine collection along with a
serum creatinine level, provides an estimate of GFR and is used to assess overall kidney
function.
Chronic Kidney Disease & Renal Failure
, Q11. Which of the following is the most common cause of end-stage renal disease
(ESRD) in the United States?
A. Polycystic kidney disease
B. Diabetes mellitus
C. Glomerulonephritis
D. Lupus nephritis
Answer: B
Rationale: Diabetes mellitus is the leading cause of ESRD in the United States, followed
by hypertension. Diabetic nephropathy results from long-term hyperglycemia damaging
the glomerular capillaries.
Q12. A GFR of less than 15 mL/min/1.73m² is classified as which stage of CKD?
A. Stage 2
B. Stage 3
C. Stage 4
D. Stage 5
Answer: D
Rationale: Stage 5 CKD (kidney failure/ESRD) is defined as a GFR less than 15
mL/min/1.73m². This stage typically requires renal replacement therapy (dialysis or
transplantation).
Q13. Which of the following signs/symptoms is most characteristic of fluid overload in
a dialysis patient?
A. Dry mucous membranes
B. Weight loss and hypotension
C. Shortness of breath, edema, and hypertension
D. Muscle cramping only
Answer: C
Rationale: Fluid overload in dialysis patients presents with shortness of breath (from
pulmonary edema), peripheral or dependent edema, hypertension, and jugular venous
distention, indicating excess interdialytic weight gain.
Q14. Uremic syndrome results from the accumulation of which substances?
A. Glucose and insulin
B. Nitrogenous waste products
C. Red blood cells
D. Vitamin D metabolites only
Questions and Answers| Latest Update| Pass Guaranteed
Comprehensive Review Covering Renal Physiology, Hemodialysis, Vascular Access,
Peritoneal Dialysis, Complications, Medications, Nutrition, Safety, and Psychosocial Care
Q1. What is the functional unit of the kidney?
A. Glomerulus
B. Nephron
C. Bowman's capsule
D. Loop of Henle
Answer: B
Rationale: The nephron is the basic structural and functional unit of the kidney. Each
kidney contains approximately one million nephrons, each consisting of a glomerulus,
Bowman's capsule, proximal tubule, loop of Henle, distal tubule, and collecting duct.
Q2. Which hormone is produced by the kidneys to stimulate red blood cell production?
A. Renin
B. Aldosterone
C. Erythropoietin
D. Calcitriol
Answer: C
Rationale: Erythropoietin (EPO) is produced by peritubular fibroblasts in the kidney in
response to hypoxia. It stimulates the bone marrow to produce red blood cells. In chronic
kidney disease, EPO production declines, leading to anemia.
Q3. Which structure is responsible for the final concentration of urine?
A. Proximal convoluted tubule
B. Loop of Henle
C. Collecting duct
D. Glomerulus
Answer: C
Rationale: The collecting duct, under the influence of antidiuretic hormone (ADH), is
responsible for the final concentration of urine by regulating water reabsorption.
Q4. Normal glomerular filtration rate (GFR) in a healthy adult is approximately:
A. 10-20 mL/min
, B. 60-70 mL/min
C. 90-120 mL/min
D. 150-180 mL/min
Answer: C
Rationale: Normal GFR in a healthy adult is approximately 90-120 mL/min/1.73m². A
GFR below 15 mL/min generally indicates kidney failure (Stage 5 CKD) requiring renal
replacement therapy.
Q5. The renin-angiotensin-aldosterone system (RAAS) primarily functions to regulate:
A. Red blood cell production
B. Blood pressure and fluid balance
C. Calcium and phosphorus balance
D. Vitamin D activation
Answer: B
Rationale: The RAAS regulates blood pressure and fluid/electrolyte balance. Renin is
released in response to low blood pressure or low sodium, ultimately leading to
angiotensin II formation and aldosterone release, which increases sodium and water
retention.
Q6. Which electrolyte is primarily regulated by aldosterone in the distal tubule?
A. Calcium
B. Sodium
C. Phosphorus
D. Magnesium
Answer: B
Rationale: Aldosterone acts on the distal convoluted tubule and collecting duct to
increase sodium reabsorption in exchange for potassium and hydrogen ion excretion.
Q7. The kidneys help maintain acid-base balance primarily by:
A. Excreting excess glucose
B. Reabsorbing bicarbonate and excreting hydrogen ions
C. Producing insulin
D. Filtering large proteins
Answer: B
,Rationale: The kidneys maintain acid-base balance by reabsorbing filtered bicarbonate
and excreting hydrogen ions as titratable acid and ammonium. This is a key function lost
in kidney failure, resulting in metabolic acidosis.
Q8. Which of the following best describes the process of diffusion in dialysis?
A. Movement of water across a semipermeable membrane due to a pressure
gradient
B. Movement of solutes from an area of higher concentration to lower concentration
C. Movement of solutes against a concentration gradient using energy
D. Movement of plasma proteins across the membrane
Answer: B
Rationale: Diffusion is the movement of solutes from an area of higher concentration to
an area of lower concentration across a semipermeable membrane. This is the primary
mechanism for solute removal in hemodialysis.
Q9. Ultrafiltration in hemodialysis refers to:
A. Removal of solutes by diffusion
B. Removal of fluid by a pressure gradient across the membrane
C. Removal of red blood cells
D. The process of clotting prevention
Answer: B
Rationale: Ultrafiltration is the removal of plasma water (fluid) across a semipermeable
membrane driven by a hydrostatic or osmotic pressure gradient (transmembrane
pressure).
Q10. Which lab value best reflects long-term kidney function over the previous 24
hours of urine collection?
A. Serum creatinine
B. Creatinine clearance
C. BUN
D. Serum potassium
Answer: B
Rationale: Creatinine clearance, calculated from a 24-hour urine collection along with a
serum creatinine level, provides an estimate of GFR and is used to assess overall kidney
function.
Chronic Kidney Disease & Renal Failure
, Q11. Which of the following is the most common cause of end-stage renal disease
(ESRD) in the United States?
A. Polycystic kidney disease
B. Diabetes mellitus
C. Glomerulonephritis
D. Lupus nephritis
Answer: B
Rationale: Diabetes mellitus is the leading cause of ESRD in the United States, followed
by hypertension. Diabetic nephropathy results from long-term hyperglycemia damaging
the glomerular capillaries.
Q12. A GFR of less than 15 mL/min/1.73m² is classified as which stage of CKD?
A. Stage 2
B. Stage 3
C. Stage 4
D. Stage 5
Answer: D
Rationale: Stage 5 CKD (kidney failure/ESRD) is defined as a GFR less than 15
mL/min/1.73m². This stage typically requires renal replacement therapy (dialysis or
transplantation).
Q13. Which of the following signs/symptoms is most characteristic of fluid overload in
a dialysis patient?
A. Dry mucous membranes
B. Weight loss and hypotension
C. Shortness of breath, edema, and hypertension
D. Muscle cramping only
Answer: C
Rationale: Fluid overload in dialysis patients presents with shortness of breath (from
pulmonary edema), peripheral or dependent edema, hypertension, and jugular venous
distention, indicating excess interdialytic weight gain.
Q14. Uremic syndrome results from the accumulation of which substances?
A. Glucose and insulin
B. Nitrogenous waste products
C. Red blood cells
D. Vitamin D metabolites only
