DaVita (RN) Final Exam ACTUAL EXAM
2026/2027 | DaVita RN Final | Verified Q&A |
Pass Guaranteed - A+ Graded
HEMODIALYSIS PRINCIPLES — Questions 1–15
Q1: During hemodialysis, urea moves from the blood compartment to the dialysate compartment
primarily through which mechanism?
A. Ultrafiltration
B. Convection
C. Diffusion [CORRECT]
D. Osmosis
Correct Answer: C
Rationale: Diffusion is the primary mechanism for solute removal in hemodialysis. Urea and other small
molecular weight solutes move across the semipermeable membrane from an area of higher
concentration (blood) to lower concentration (dialysate) along the concentration gradient. The
countercurrent flow design maximizes this gradient along the entire length of the dialyzer.
Q2: A patient requires removal of 3.5 kg of fluid during a 4-hour dialysis treatment. What is the required
ultrafiltration rate?
A. 500 mL/hr
B. 875 mL/hr [CORRECT]
C. 1,000 mL/hr
D. 1,200 mL/hr
Correct Answer: B
Rationale: Ultrafiltration rate calculation: 3.5 kg = 3,500 mL. 3,500 mL ÷ 4 hours = 875 mL/hr. The
ultrafiltration rate should generally not exceed 10–13 mL/kg/hr to minimize intradialytic hypotension
and cramping. For a 70 kg patient, 875 mL/hr = 12.5 mL/kg/hr, which is at the upper acceptable limit.
Q3: Which characteristic best describes a high-flux dialyzer membrane?
,A. Pore size that allows only small solutes (urea, creatinine) to pass
B. Increased permeability to middle molecules (β2-microglobulin, 11,800 Da) [CORRECT]
C. Requires lower blood flow rates for equivalent clearance
D. Cannot be used with standard dialysis machines
Correct Answer: B
Rationale: High-flux dialyzers have larger pore sizes and higher hydraulic permeability (KUF >20
mL/hr/mmHg), allowing removal of middle molecules such as β2-microglobulin (11,800 Da) in addition
to small solutes. This reduces amyloidosis risk. High-flux membranes require standard blood flow rates
(300–500 mL/min) and are compatible with all modern dialysis machines.
Q4: In countercurrent flow dialysis, blood and dialysate flow in opposite directions. What is the primary
advantage of this design?
A. Reduces the risk of air embolism
B. Maintains a concentration gradient along the entire dialyzer length [CORRECT]
C. Allows for higher ultrafiltration rates
D. Prevents dialyzer clotting
Correct Answer: B
Rationale: Countercurrent flow maintains the steepest possible concentration gradient between blood
and dialysate along the entire length of the dialyzer. If flows were concurrent, the gradient would
diminish as fluids approached equilibrium. This design maximizes solute clearance efficiency and is
standard in all modern dialyzers.
Q5: A patient's dialysate sodium is set at 138 mEq/L. The patient's serum sodium is 140 mEq/L. Which
direction will sodium move during dialysis?
A. From dialysate to blood
B. From blood to dialysate [CORRECT]
C. No net movement will occur
D. Movement depends on blood flow rate
Correct Answer: B
Rationale: Sodium moves by diffusion from higher to lower concentration. With serum sodium (140
mEq/L) higher than dialysate sodium (138 mEq/L), sodium will move from blood to dialysate. This 2
mEq/L gradient promotes mild sodium removal. Dialysate sodium is typically set between 135–140
mEq/L; lower settings increase sodium removal but may precipitate hypotension and cramping.
,Q6: Which solute is primarily removed by convection rather than diffusion during hemodialysis?
A. Urea (60 Da)
B. Creatinine (113 Da)
C. β2-microglobulin (11,800 Da)
D. Phosphate (96 Da)
Correct Answer: C
Rationale: Convection (solvent drag) is the primary mechanism for middle molecule removal such as
β2-microglobulin (11,800 Da) during high-flux dialysis and hemodiafiltration. Small solutes (urea,
creatinine, phosphate) are primarily removed by diffusion. Convection becomes increasingly important
as molecular weight increases beyond 1,000 Da.
Q7: A patient is receiving dialysis with a dialysate temperature of 36.5°C. The patient reports feeling cold
and shivering. Which adjustment should the RN consider?
A. Increase the dialysate temperature to 38.0°C
B. Increase the dialysate temperature to 37.0°C and assess for sepsis [CORRECT]
C. Decrease the dialysate temperature to 35.5°C to improve clearance
D. No adjustment; cold intolerance is expected during dialysis
Correct Answer: B
Rationale: Standard dialysate temperature is 35.5–37.0°C. A patient feeling cold with shivering may
indicate dialysate temperature too low or sepsis. The RN should increase dialysate temperature toward
37.0°C and assess for infection (temperature, WBC, access site, other symptoms). Temperatures >37.0°C
increase risk of hemodynamic instability; temperatures <35.5°C cause discomfort and may mask fever.
Q8: The principle of ultrafiltration in hemodialysis is best described as:
A. Movement of solutes across a concentration gradient
B. Movement of fluid across a hydrostatic or osmotic pressure gradient [CORRECT]
C. Binding of toxins to dialysate components
D. Active transport of electrolytes against their gradient
Correct Answer: B
Rationale: Ultrafiltration is the movement of plasma water across the semipermeable membrane
driven by a transmembrane pressure (TMP) gradient — the difference between hydrostatic pressure in
the blood compartment and dialysate compartment, plus any oncotic pressure effects. This removes
excess fluid volume. It is distinct from diffusion (solute movement by concentration gradient) and
convection (solute drag with fluid).
, Q9: A patient has a serum potassium of 5.8 mEq/L predialysis. Which dialysate potassium concentration
is most appropriate?
A. 4.0 mEq/L
B. 3.0 mEq/L
C. 2.0 mEq/L [CORRECT]
D. 1.0 mEq/L
Correct Answer: C
Rationale: For moderate hyperkalemia (5.5–6.0 mEq/L), a 2.0 mEq/L dialysate potassium provides a
safe gradient for potassium removal without precipitating rapid shifts that cause arrhythmias. A 1.0
mEq/L bath (D) is reserved for severe hyperkalemia (>6.0 mEq/L) or life-threatening arrhythmias due to
risk of rebound hypokalemia post-dialysis. Higher baths (A, B) are used for normokalemia or
hypokalemia.
Q10: Which factor most significantly increases the efficiency of small solute clearance (Kt/V) during
hemodialysis?
A. Increasing dialysate flow rate from 500 to 800 mL/min
B. Increasing blood flow rate from 250 to 400 mL/min [CORRECT]
C. Decreasing dialysate temperature by 1.0°C
D. Increasing treatment time by 15 minutes
Correct Answer: B
Rationale: Blood flow rate (Qb) is the most significant determinant of small solute clearance. Increasing
Qb from 250 to 400 mL/min substantially increases urea and creatinine clearance by delivering more
solute-rich blood to the dialyzer membrane per unit time. Dialysate flow (A) has diminishing returns
above 500 mL/min; temperature (C) affects hemodynamics, not clearance; time (D) helps but is less
impactful than Qb.
Q11: A patient asks why they feel better after dialysis. The RN explains that dialysis removes uremic
toxins. Which toxin accumulation is most associated with uremic neuropathy?
A. Urea
B. Creatinine
C. β2-microglobulin
D. Middle molecules (parathyroid hormone, advanced glycation end-products) [CORRECT]
2026/2027 | DaVita RN Final | Verified Q&A |
Pass Guaranteed - A+ Graded
HEMODIALYSIS PRINCIPLES — Questions 1–15
Q1: During hemodialysis, urea moves from the blood compartment to the dialysate compartment
primarily through which mechanism?
A. Ultrafiltration
B. Convection
C. Diffusion [CORRECT]
D. Osmosis
Correct Answer: C
Rationale: Diffusion is the primary mechanism for solute removal in hemodialysis. Urea and other small
molecular weight solutes move across the semipermeable membrane from an area of higher
concentration (blood) to lower concentration (dialysate) along the concentration gradient. The
countercurrent flow design maximizes this gradient along the entire length of the dialyzer.
Q2: A patient requires removal of 3.5 kg of fluid during a 4-hour dialysis treatment. What is the required
ultrafiltration rate?
A. 500 mL/hr
B. 875 mL/hr [CORRECT]
C. 1,000 mL/hr
D. 1,200 mL/hr
Correct Answer: B
Rationale: Ultrafiltration rate calculation: 3.5 kg = 3,500 mL. 3,500 mL ÷ 4 hours = 875 mL/hr. The
ultrafiltration rate should generally not exceed 10–13 mL/kg/hr to minimize intradialytic hypotension
and cramping. For a 70 kg patient, 875 mL/hr = 12.5 mL/kg/hr, which is at the upper acceptable limit.
Q3: Which characteristic best describes a high-flux dialyzer membrane?
,A. Pore size that allows only small solutes (urea, creatinine) to pass
B. Increased permeability to middle molecules (β2-microglobulin, 11,800 Da) [CORRECT]
C. Requires lower blood flow rates for equivalent clearance
D. Cannot be used with standard dialysis machines
Correct Answer: B
Rationale: High-flux dialyzers have larger pore sizes and higher hydraulic permeability (KUF >20
mL/hr/mmHg), allowing removal of middle molecules such as β2-microglobulin (11,800 Da) in addition
to small solutes. This reduces amyloidosis risk. High-flux membranes require standard blood flow rates
(300–500 mL/min) and are compatible with all modern dialysis machines.
Q4: In countercurrent flow dialysis, blood and dialysate flow in opposite directions. What is the primary
advantage of this design?
A. Reduces the risk of air embolism
B. Maintains a concentration gradient along the entire dialyzer length [CORRECT]
C. Allows for higher ultrafiltration rates
D. Prevents dialyzer clotting
Correct Answer: B
Rationale: Countercurrent flow maintains the steepest possible concentration gradient between blood
and dialysate along the entire length of the dialyzer. If flows were concurrent, the gradient would
diminish as fluids approached equilibrium. This design maximizes solute clearance efficiency and is
standard in all modern dialyzers.
Q5: A patient's dialysate sodium is set at 138 mEq/L. The patient's serum sodium is 140 mEq/L. Which
direction will sodium move during dialysis?
A. From dialysate to blood
B. From blood to dialysate [CORRECT]
C. No net movement will occur
D. Movement depends on blood flow rate
Correct Answer: B
Rationale: Sodium moves by diffusion from higher to lower concentration. With serum sodium (140
mEq/L) higher than dialysate sodium (138 mEq/L), sodium will move from blood to dialysate. This 2
mEq/L gradient promotes mild sodium removal. Dialysate sodium is typically set between 135–140
mEq/L; lower settings increase sodium removal but may precipitate hypotension and cramping.
,Q6: Which solute is primarily removed by convection rather than diffusion during hemodialysis?
A. Urea (60 Da)
B. Creatinine (113 Da)
C. β2-microglobulin (11,800 Da)
D. Phosphate (96 Da)
Correct Answer: C
Rationale: Convection (solvent drag) is the primary mechanism for middle molecule removal such as
β2-microglobulin (11,800 Da) during high-flux dialysis and hemodiafiltration. Small solutes (urea,
creatinine, phosphate) are primarily removed by diffusion. Convection becomes increasingly important
as molecular weight increases beyond 1,000 Da.
Q7: A patient is receiving dialysis with a dialysate temperature of 36.5°C. The patient reports feeling cold
and shivering. Which adjustment should the RN consider?
A. Increase the dialysate temperature to 38.0°C
B. Increase the dialysate temperature to 37.0°C and assess for sepsis [CORRECT]
C. Decrease the dialysate temperature to 35.5°C to improve clearance
D. No adjustment; cold intolerance is expected during dialysis
Correct Answer: B
Rationale: Standard dialysate temperature is 35.5–37.0°C. A patient feeling cold with shivering may
indicate dialysate temperature too low or sepsis. The RN should increase dialysate temperature toward
37.0°C and assess for infection (temperature, WBC, access site, other symptoms). Temperatures >37.0°C
increase risk of hemodynamic instability; temperatures <35.5°C cause discomfort and may mask fever.
Q8: The principle of ultrafiltration in hemodialysis is best described as:
A. Movement of solutes across a concentration gradient
B. Movement of fluid across a hydrostatic or osmotic pressure gradient [CORRECT]
C. Binding of toxins to dialysate components
D. Active transport of electrolytes against their gradient
Correct Answer: B
Rationale: Ultrafiltration is the movement of plasma water across the semipermeable membrane
driven by a transmembrane pressure (TMP) gradient — the difference between hydrostatic pressure in
the blood compartment and dialysate compartment, plus any oncotic pressure effects. This removes
excess fluid volume. It is distinct from diffusion (solute movement by concentration gradient) and
convection (solute drag with fluid).
, Q9: A patient has a serum potassium of 5.8 mEq/L predialysis. Which dialysate potassium concentration
is most appropriate?
A. 4.0 mEq/L
B. 3.0 mEq/L
C. 2.0 mEq/L [CORRECT]
D. 1.0 mEq/L
Correct Answer: C
Rationale: For moderate hyperkalemia (5.5–6.0 mEq/L), a 2.0 mEq/L dialysate potassium provides a
safe gradient for potassium removal without precipitating rapid shifts that cause arrhythmias. A 1.0
mEq/L bath (D) is reserved for severe hyperkalemia (>6.0 mEq/L) or life-threatening arrhythmias due to
risk of rebound hypokalemia post-dialysis. Higher baths (A, B) are used for normokalemia or
hypokalemia.
Q10: Which factor most significantly increases the efficiency of small solute clearance (Kt/V) during
hemodialysis?
A. Increasing dialysate flow rate from 500 to 800 mL/min
B. Increasing blood flow rate from 250 to 400 mL/min [CORRECT]
C. Decreasing dialysate temperature by 1.0°C
D. Increasing treatment time by 15 minutes
Correct Answer: B
Rationale: Blood flow rate (Qb) is the most significant determinant of small solute clearance. Increasing
Qb from 250 to 400 mL/min substantially increases urea and creatinine clearance by delivering more
solute-rich blood to the dialyzer membrane per unit time. Dialysate flow (A) has diminishing returns
above 500 mL/min; temperature (C) affects hemodynamics, not clearance; time (D) helps but is less
impactful than Qb.
Q11: A patient asks why they feel better after dialysis. The RN explains that dialysis removes uremic
toxins. Which toxin accumulation is most associated with uremic neuropathy?
A. Urea
B. Creatinine
C. β2-microglobulin
D. Middle molecules (parathyroid hormone, advanced glycation end-products) [CORRECT]
