Davita Study Guide Exam Questions And
Correct Answers
Instructions: This study guide contains multiple-choice questions covering the core content
tested on DaVita PCT competency examinations and the national CCHT certification. Topics
include dialysis principles, water treatment, vascular access, patient monitoring,
complications, and infection control.
1. What is the primary physiological principle by which hemodialysis removes
urea and creatinine from the blood?
A. Osmosis driven by hydrostatic pressure
B. Diffusion across a semipermeable membrane along a concentration gradient
C. Active transport via cellular pumps in the dialyzer
D. Filtration solely through gravitational force
Correct Answer: B — Diffusion across a semipermeable membrane along a
concentration gradient
Rationale: Hemodialysis relies primarily on diffusion, where solutes such as urea
and creatinine move from an area of higher concentration in the blood to an
area of lower concentration in the dialysate across a semipermeable
membrane. This passive process is fundamental to toxin removal, whereas
osmosis primarily governs fluid removal .
,2. Which water treatment component is responsible for removing chlorine and
chloramines from the water supply?
A. Sediment filter
B. Carbon tanks (activated carbon filtration)
C. Reverse osmosis (RO) unit
D. Deionization (DI) tanks
Correct Answer: B — Carbon tanks (activated carbon filtration)
Rationale: Activated carbon filtration removes chlorine and chloramines
through adsorption. These substances are toxic to patients and can cause
hemolysis if not removed. Carbon tanks are typically arranged in a dual-tank
configuration .
3. What is the maximum allowable level of total chlorine in dialysis water
according to AAMI standards?
A. 0.1 mg/L (ppm)
B. 0.5 mg/L (ppm)
C. 1.0 mg/L (ppm)
D. 2.0 mg/L (ppm)
,Correct Answer: A — 0.1 mg/L (ppm)
Rationale: The Association for the Advancement of Medical Instrumentation
(AAMI) sets the maximum allowable limit for total chlorine in dialysis water at
0.1 mg/L (ppm) to prevent hemolysis and other toxic reactions in patients .
4. Which vascular access type is considered the gold standard for long-term
hemodialysis due to superior patency and lower infection rates?
A. Tunneled cuffed central venous catheter
B. Non-tunneled temporary catheter
C. Arteriovenous fistula
D. Arteriovenous graft
Correct Answer: C — Arteriovenous fistula
Rationale: An arteriovenous (AV) fistula, created by surgically connecting an
artery to a vein, is the preferred vascular access for hemodialysis because it has
the lowest rates of infection, thrombosis, and stenosis, and provides adequate
blood flow for effective dialysis over many years .
5. During hemodialysis, what is the primary purpose of monitoring the patient's
transmembrane pressure (TMP)?
, A. To assess the patient's blood pressure stability
B. To evaluate the efficiency of solute clearance
C. To detect potential dialyzer clotting or membrane integrity issues
D. To calculate the patient's dry weight
Correct Answer: C — To detect potential dialyzer clotting or membrane integrity
issues
Rationale: Transmembrane pressure (TMP) reflects the pressure gradient across
the dialyzer membrane. Abnormal TMP values can indicate dialyzer clotting
(elevated TMP) or membrane rupture (sudden drop in TMP), both of which
compromise treatment safety and efficacy .
6. Which laboratory value is most critical to monitor immediately before
initiating a hemodialysis session to prevent life-threatening complications?
A. Hemoglobin level
B. Serum potassium level
C. Albumin level
D. White blood cell count
Correct Answer: B — Serum potassium level
Correct Answers
Instructions: This study guide contains multiple-choice questions covering the core content
tested on DaVita PCT competency examinations and the national CCHT certification. Topics
include dialysis principles, water treatment, vascular access, patient monitoring,
complications, and infection control.
1. What is the primary physiological principle by which hemodialysis removes
urea and creatinine from the blood?
A. Osmosis driven by hydrostatic pressure
B. Diffusion across a semipermeable membrane along a concentration gradient
C. Active transport via cellular pumps in the dialyzer
D. Filtration solely through gravitational force
Correct Answer: B — Diffusion across a semipermeable membrane along a
concentration gradient
Rationale: Hemodialysis relies primarily on diffusion, where solutes such as urea
and creatinine move from an area of higher concentration in the blood to an
area of lower concentration in the dialysate across a semipermeable
membrane. This passive process is fundamental to toxin removal, whereas
osmosis primarily governs fluid removal .
,2. Which water treatment component is responsible for removing chlorine and
chloramines from the water supply?
A. Sediment filter
B. Carbon tanks (activated carbon filtration)
C. Reverse osmosis (RO) unit
D. Deionization (DI) tanks
Correct Answer: B — Carbon tanks (activated carbon filtration)
Rationale: Activated carbon filtration removes chlorine and chloramines
through adsorption. These substances are toxic to patients and can cause
hemolysis if not removed. Carbon tanks are typically arranged in a dual-tank
configuration .
3. What is the maximum allowable level of total chlorine in dialysis water
according to AAMI standards?
A. 0.1 mg/L (ppm)
B. 0.5 mg/L (ppm)
C. 1.0 mg/L (ppm)
D. 2.0 mg/L (ppm)
,Correct Answer: A — 0.1 mg/L (ppm)
Rationale: The Association for the Advancement of Medical Instrumentation
(AAMI) sets the maximum allowable limit for total chlorine in dialysis water at
0.1 mg/L (ppm) to prevent hemolysis and other toxic reactions in patients .
4. Which vascular access type is considered the gold standard for long-term
hemodialysis due to superior patency and lower infection rates?
A. Tunneled cuffed central venous catheter
B. Non-tunneled temporary catheter
C. Arteriovenous fistula
D. Arteriovenous graft
Correct Answer: C — Arteriovenous fistula
Rationale: An arteriovenous (AV) fistula, created by surgically connecting an
artery to a vein, is the preferred vascular access for hemodialysis because it has
the lowest rates of infection, thrombosis, and stenosis, and provides adequate
blood flow for effective dialysis over many years .
5. During hemodialysis, what is the primary purpose of monitoring the patient's
transmembrane pressure (TMP)?
, A. To assess the patient's blood pressure stability
B. To evaluate the efficiency of solute clearance
C. To detect potential dialyzer clotting or membrane integrity issues
D. To calculate the patient's dry weight
Correct Answer: C — To detect potential dialyzer clotting or membrane integrity
issues
Rationale: Transmembrane pressure (TMP) reflects the pressure gradient across
the dialyzer membrane. Abnormal TMP values can indicate dialyzer clotting
(elevated TMP) or membrane rupture (sudden drop in TMP), both of which
compromise treatment safety and efficacy .
6. Which laboratory value is most critical to monitor immediately before
initiating a hemodialysis session to prevent life-threatening complications?
A. Hemoglobin level
B. Serum potassium level
C. Albumin level
D. White blood cell count
Correct Answer: B — Serum potassium level
