NEPHROLOGY TEST PAPER 2025/2026 QUESTIONS AND
SOLUTIONS GRADED A+ TIP
✔✔A pt with CKD category G4 (eGFR 25) has received a diagnosis of gram-positive
bacteremia, which is susceptible only to drug X. There are no published reports on how
to adjust the dose of drug X in patients with impaired kidney function. Review of the
drug X package insert shows that drug X has significant renal elimination, with 40%
excreted unchanged in the urine. The usual dose for drug X is 600 mg/day
intravenously and is provided as 100 mg/mL in a 6-mL vial. Which is the best dose (in
milliliters of drug X) for this patient?
A. 3.6.
B. 4.1.
C. 4.5.
D. 5.5. - ✔✔B. 4.1
Information regarding the fraction of drug excreted in the urine (Fe) can help determine
the proper dose of a drug when specific dosing guidelines are not available. The
Rowland-Tozer equation can determine the percentage of the usual dose to give a
patient with known kidney disease (Q), considering the ratio of the patient's renal
function to normal (KF).
For a patient with an estimated CrCl of 25,
Q = 1 − [Fe(1 − KF)] =
1 − [0.4(1 − 25/120)] =
1 − 0.32 = 0.68, or 68% of the usual dose. If the usual dose is 600 mg, the adjusted
dose would be 410 mg (600 mg × 0.68). Thus, the patient should receive 4.1 mL of the
100-mg/ mL preparation (410 mg/100 mg/mL) (Answer B is correct; Answers A, C, and
D are incorrect).
✔✔A 45/M (wt 59 kg, ht 70 in) has a long history of cancer and malnutrition. His SCr is
0.5. Carboplatin will be initiated, for which an accurate estimate of kidney function is
critical. Which is the best method for assessing kidney function in this patient?
A. Cockcroft-Gault equation.
B. Modification of Diet in Renal Disease (MDRD) study equation.
C. 24-hour urine collection.
D. Iothalamate study - ✔✔C. 24 h urine collection
In most cases, either the Cockcroft-Gault or the MDRD equation is appropriate (and
best) to assess kidney function. However, this patient is significantly below his ideal
body weight and has malnutrition, so these equations would likely overestimate his
renal function (Answers A and B are incorrect). An iothalamate study will measure GFR
but is not used clinically (Answer D is incorrect). A timed urine collection (Answer C) is
best to assess kidney function. However, the urine collection must be complete to
ensure an accurate measurement of renal function.
,✔✔A 59 y/o who has had CKD category G5D for 10 years has HTN, CAD, mild CHF,
and T2DM. Meds are as follows: epoetin 10,000 units IV three times/week at dialysis,
renal multivitamin once daily, atorvastatin 20 mg/day, insulin, and calcium acetate 1334
mg TID with meals. Labs are as follows: Hgb 9.2, intact PTH 300 pg/mL, Na 140, K 4.9,
SCr 7.0, calcium 9, albumin 3.5, and phosphorus 4.8. His serum ferritin concentration is
80 ng/mL and TSAT is 14%. Mean corpuscular volume, mean corpuscular hemoglobin
concentration, and WBC are all normal. He is afebrile. Which is best for managing this
patient's anemia?
A. Increase epoetin.
B. Add oral iron.
C. Add intravenous iron.
D. Maintain current regimen; patient is at goal. - ✔✔C. Add intravenous iron.
This patient's Hgb is not at goal (greater than 10 g/dL), so maintaining the current
regimen would not be appropriate (Answer D is incorrect).
Iron studies show the patient is iron deficient, with TSAT less than 30% and ferritin less
than 500 ng/mL (Answer A is incorrect). Increasing the epoetin dose would not increase
red blood cell production in the absence of adequate iron. Although a trial of oral iron
might be indicated in non- dialysis patients with CKD, patients on HD should be given
intravenous iron as first line (Answer B is incorrect; Answer C is correct).
✔✔A 60 y/o (wt 72 kg) w/ a hx of DM and HTN is in the ICU after having a MI about 1
week ago with secondary HF. He now has pneumonia. He has been hypotensive for the
past 5 days. Before his admission 1 week ago, his SCr was 1.0. His urinary output has
steadily been declining for the past 3 days, despite adequate hydration, with 700 mL of
urinary output in the past 24 hours. His meds include IV dobutamine, nitroglycerin, and
cefazolin. Yesterday, his BUN and SCr were 32 and 3.1, respectively; today, they are
41 and 3.9 mg/dL. His urinary osmolality is 290. His urinary sodium is 45 mEq/L, and
there are tubular cellular casts in his urine. Which is the most likely renal diagnosis?
A. Prerenal azotemia.
B. Acute tubular necrosis
C. Acute interstitial nephritis (AIN).
D. Hemodynamic/functional-mediated acute kidney injury (AKI). - ✔✔B. Acute tubular
necrosis
The presence of hypotension despite adequate hydration, a normal BUN/SCr ratio (10-
15:1), urinary osmolality, and presence of urinary casts all point to ATN (Answer B is
correct).
Prerenal AKI is unlikely, considering adequate hydration, high urinary sodium (greater
than 40 mEq/L), and lack of high urinary osmolality (Answer A is incorrect).
Functional AKI would look similar to prerenal AKI on urinalysis with low urinary sodium
and no tubular casts (Answer D is incorrect).
,Classically, AIN would present with eosinophils in the urine (Answer C is incorrect).
✔✔You are evaluating a study comparing epoetin and darbepoetin with respect to their
efficacy on mean Hgb concentrations. Both drugs are initiated at the recommended
dose, and the Hgb concentration is checked at 4 weeks. Fifty patients are in each
group. The mean Hgb in the epoetin group is 12.1 g/dL and is 12.2 g/dL in the
darbepoetin group. Which statistical test is best for this comparison?
A. Paired t-test.
B. Independent (unpaired) t-test.
C. Analysis of variance.
D. Chi-square test. - ✔✔B. Independent (unpaired) t-test.
Scientific experiments often consist of comparing two or more sets of data. This data is
described as unpaired or independent when the sets of data arise from separate
individuals or paired when it arises from the same individual at different points in time.
Hemoglobin represents continuous data. Because each treatment is administered to a
separate group of patients, the data are not paired (i.e., they are unpaired) (Answer A is
incorrect).
Assuming the data are normally distributed, continuous unpaired data should be
evaluated using a t-test (Answer B is correct).
Analysis of variance can be used for continuous data, but only when three groups of
data are compared (Answer C is incorrect). A chi-square test is used for nominal data
(Answer D is incorrect).
✔✔A pharmacoeconomic study compared the use of erythropoiesis-stimulating agents
with various Hgb concentrations. The primary outcome of this study was cost per
quality-adjusted life-year gained. Which best describes this economic evaluation?
A. Cost-minimization.
B. Cost-effectiveness.
C. Cost-benefit.
D. Cost-utility - ✔✔D. Cost-utility
A cost-utility analysis is an extension of the cost effectiveness analysis in which the
outcomes measured are lives saved, adjusted for changes in quality of life, measured
as quality-adjusted life-years (Answer D is correct).
A cost-minimization study compares the costs and consequences of two or more
interventions that have equivalent outcomes, so the primary focus is on cost (Answer A
is incorrect).
A cost-effectiveness analysis compares costs and consequences to determine which
treatment can achieve the best outcomes at the lowest cost (Answer B is incorrect).
, A cost-benefit analysis measures costs and consequences in monetary terms; this
analysis may be useful to compare costs with unrelated outcomes (Answer C is
incorrect).
✔✔A 58-year-old woman is being evaluated for AKI. Labs include serum Na 134, BUN
35, SCr 1.8, urinary sodium 24, and urinary creatinine 14.3. Which is the best estimate
of this patient's FENa?
A. 0.8%.
B. 1.25%.
C. 2.3%.
D. 4.4% - ✔✔C. 2.3%
(UNa x SCr) / (UCr x SNa)
Always start w/ UNa then just use your opposites
Calculating the FENa helps assess AKI to help differentiate prerenal from ATN:
FENa = [(urinary sodium)/ (serum sodium)]/[(urinary creatinine)/(SCr)] × 100 =
[(24 mEq/L)/(134 mEq/L)]/[(14.3 mg/dL)/(1.8 mg/dL)] × 100 = 2.3% (Answer C is
correct).
This FENa greater than 2% would be most consistent with ATN (Answers A, B, and D
are incorrect).
✔✔A 55/M has a history of HTN. His eGFR is 48 and urinary albumin/creatinine ratio
(ACR) is 28 mg/g. Which best depicts what this patient's goal blood pressure should be
less than, according to the Kidney Disease: Improving Global Outcomes (KDIGO)
guidelines?
A. 130/80 mm Hg.
B. 140/90 mm Hg.
C. 140/80 mm Hg.
D. 130/90 mm Hg. - ✔✔B. 140/90 mm Hg.
The KDIGO guidelines provide recommendations for blood pressure goals for patients
with CKD according to the severity of proteinuria. This patient is considered to have
normal to mildly elevated albuminuria, with an ACR less than 30 mg/g. Patients with
albuminuria in this category (A1) should have a goal blood pressure of less than 140/90
mm Hg (Answer B is correct).
A goal blood pressure of less than 130/80 mm Hg would be desired for a patient with
moderate to severe (category A2) albuminuria (Answer A is incorrect). Answer C is
incorrect because the diastolic blood pressure goal is too low (80 mm Hg). Answer D is
incorrect because the systolic blood pressure goal is too low (130 mm Hg).
✔✔A 66/M has an eGFR of 55. His albumin/creatinine ratio is 100 mg/g. His Hgb is
currently 13.2 g/dL, with normal RBC indices without treatment. Which best reflects the
recommended minimum frequency of Hgb monitoring in this patient?
SOLUTIONS GRADED A+ TIP
✔✔A pt with CKD category G4 (eGFR 25) has received a diagnosis of gram-positive
bacteremia, which is susceptible only to drug X. There are no published reports on how
to adjust the dose of drug X in patients with impaired kidney function. Review of the
drug X package insert shows that drug X has significant renal elimination, with 40%
excreted unchanged in the urine. The usual dose for drug X is 600 mg/day
intravenously and is provided as 100 mg/mL in a 6-mL vial. Which is the best dose (in
milliliters of drug X) for this patient?
A. 3.6.
B. 4.1.
C. 4.5.
D. 5.5. - ✔✔B. 4.1
Information regarding the fraction of drug excreted in the urine (Fe) can help determine
the proper dose of a drug when specific dosing guidelines are not available. The
Rowland-Tozer equation can determine the percentage of the usual dose to give a
patient with known kidney disease (Q), considering the ratio of the patient's renal
function to normal (KF).
For a patient with an estimated CrCl of 25,
Q = 1 − [Fe(1 − KF)] =
1 − [0.4(1 − 25/120)] =
1 − 0.32 = 0.68, or 68% of the usual dose. If the usual dose is 600 mg, the adjusted
dose would be 410 mg (600 mg × 0.68). Thus, the patient should receive 4.1 mL of the
100-mg/ mL preparation (410 mg/100 mg/mL) (Answer B is correct; Answers A, C, and
D are incorrect).
✔✔A 45/M (wt 59 kg, ht 70 in) has a long history of cancer and malnutrition. His SCr is
0.5. Carboplatin will be initiated, for which an accurate estimate of kidney function is
critical. Which is the best method for assessing kidney function in this patient?
A. Cockcroft-Gault equation.
B. Modification of Diet in Renal Disease (MDRD) study equation.
C. 24-hour urine collection.
D. Iothalamate study - ✔✔C. 24 h urine collection
In most cases, either the Cockcroft-Gault or the MDRD equation is appropriate (and
best) to assess kidney function. However, this patient is significantly below his ideal
body weight and has malnutrition, so these equations would likely overestimate his
renal function (Answers A and B are incorrect). An iothalamate study will measure GFR
but is not used clinically (Answer D is incorrect). A timed urine collection (Answer C) is
best to assess kidney function. However, the urine collection must be complete to
ensure an accurate measurement of renal function.
,✔✔A 59 y/o who has had CKD category G5D for 10 years has HTN, CAD, mild CHF,
and T2DM. Meds are as follows: epoetin 10,000 units IV three times/week at dialysis,
renal multivitamin once daily, atorvastatin 20 mg/day, insulin, and calcium acetate 1334
mg TID with meals. Labs are as follows: Hgb 9.2, intact PTH 300 pg/mL, Na 140, K 4.9,
SCr 7.0, calcium 9, albumin 3.5, and phosphorus 4.8. His serum ferritin concentration is
80 ng/mL and TSAT is 14%. Mean corpuscular volume, mean corpuscular hemoglobin
concentration, and WBC are all normal. He is afebrile. Which is best for managing this
patient's anemia?
A. Increase epoetin.
B. Add oral iron.
C. Add intravenous iron.
D. Maintain current regimen; patient is at goal. - ✔✔C. Add intravenous iron.
This patient's Hgb is not at goal (greater than 10 g/dL), so maintaining the current
regimen would not be appropriate (Answer D is incorrect).
Iron studies show the patient is iron deficient, with TSAT less than 30% and ferritin less
than 500 ng/mL (Answer A is incorrect). Increasing the epoetin dose would not increase
red blood cell production in the absence of adequate iron. Although a trial of oral iron
might be indicated in non- dialysis patients with CKD, patients on HD should be given
intravenous iron as first line (Answer B is incorrect; Answer C is correct).
✔✔A 60 y/o (wt 72 kg) w/ a hx of DM and HTN is in the ICU after having a MI about 1
week ago with secondary HF. He now has pneumonia. He has been hypotensive for the
past 5 days. Before his admission 1 week ago, his SCr was 1.0. His urinary output has
steadily been declining for the past 3 days, despite adequate hydration, with 700 mL of
urinary output in the past 24 hours. His meds include IV dobutamine, nitroglycerin, and
cefazolin. Yesterday, his BUN and SCr were 32 and 3.1, respectively; today, they are
41 and 3.9 mg/dL. His urinary osmolality is 290. His urinary sodium is 45 mEq/L, and
there are tubular cellular casts in his urine. Which is the most likely renal diagnosis?
A. Prerenal azotemia.
B. Acute tubular necrosis
C. Acute interstitial nephritis (AIN).
D. Hemodynamic/functional-mediated acute kidney injury (AKI). - ✔✔B. Acute tubular
necrosis
The presence of hypotension despite adequate hydration, a normal BUN/SCr ratio (10-
15:1), urinary osmolality, and presence of urinary casts all point to ATN (Answer B is
correct).
Prerenal AKI is unlikely, considering adequate hydration, high urinary sodium (greater
than 40 mEq/L), and lack of high urinary osmolality (Answer A is incorrect).
Functional AKI would look similar to prerenal AKI on urinalysis with low urinary sodium
and no tubular casts (Answer D is incorrect).
,Classically, AIN would present with eosinophils in the urine (Answer C is incorrect).
✔✔You are evaluating a study comparing epoetin and darbepoetin with respect to their
efficacy on mean Hgb concentrations. Both drugs are initiated at the recommended
dose, and the Hgb concentration is checked at 4 weeks. Fifty patients are in each
group. The mean Hgb in the epoetin group is 12.1 g/dL and is 12.2 g/dL in the
darbepoetin group. Which statistical test is best for this comparison?
A. Paired t-test.
B. Independent (unpaired) t-test.
C. Analysis of variance.
D. Chi-square test. - ✔✔B. Independent (unpaired) t-test.
Scientific experiments often consist of comparing two or more sets of data. This data is
described as unpaired or independent when the sets of data arise from separate
individuals or paired when it arises from the same individual at different points in time.
Hemoglobin represents continuous data. Because each treatment is administered to a
separate group of patients, the data are not paired (i.e., they are unpaired) (Answer A is
incorrect).
Assuming the data are normally distributed, continuous unpaired data should be
evaluated using a t-test (Answer B is correct).
Analysis of variance can be used for continuous data, but only when three groups of
data are compared (Answer C is incorrect). A chi-square test is used for nominal data
(Answer D is incorrect).
✔✔A pharmacoeconomic study compared the use of erythropoiesis-stimulating agents
with various Hgb concentrations. The primary outcome of this study was cost per
quality-adjusted life-year gained. Which best describes this economic evaluation?
A. Cost-minimization.
B. Cost-effectiveness.
C. Cost-benefit.
D. Cost-utility - ✔✔D. Cost-utility
A cost-utility analysis is an extension of the cost effectiveness analysis in which the
outcomes measured are lives saved, adjusted for changes in quality of life, measured
as quality-adjusted life-years (Answer D is correct).
A cost-minimization study compares the costs and consequences of two or more
interventions that have equivalent outcomes, so the primary focus is on cost (Answer A
is incorrect).
A cost-effectiveness analysis compares costs and consequences to determine which
treatment can achieve the best outcomes at the lowest cost (Answer B is incorrect).
, A cost-benefit analysis measures costs and consequences in monetary terms; this
analysis may be useful to compare costs with unrelated outcomes (Answer C is
incorrect).
✔✔A 58-year-old woman is being evaluated for AKI. Labs include serum Na 134, BUN
35, SCr 1.8, urinary sodium 24, and urinary creatinine 14.3. Which is the best estimate
of this patient's FENa?
A. 0.8%.
B. 1.25%.
C. 2.3%.
D. 4.4% - ✔✔C. 2.3%
(UNa x SCr) / (UCr x SNa)
Always start w/ UNa then just use your opposites
Calculating the FENa helps assess AKI to help differentiate prerenal from ATN:
FENa = [(urinary sodium)/ (serum sodium)]/[(urinary creatinine)/(SCr)] × 100 =
[(24 mEq/L)/(134 mEq/L)]/[(14.3 mg/dL)/(1.8 mg/dL)] × 100 = 2.3% (Answer C is
correct).
This FENa greater than 2% would be most consistent with ATN (Answers A, B, and D
are incorrect).
✔✔A 55/M has a history of HTN. His eGFR is 48 and urinary albumin/creatinine ratio
(ACR) is 28 mg/g. Which best depicts what this patient's goal blood pressure should be
less than, according to the Kidney Disease: Improving Global Outcomes (KDIGO)
guidelines?
A. 130/80 mm Hg.
B. 140/90 mm Hg.
C. 140/80 mm Hg.
D. 130/90 mm Hg. - ✔✔B. 140/90 mm Hg.
The KDIGO guidelines provide recommendations for blood pressure goals for patients
with CKD according to the severity of proteinuria. This patient is considered to have
normal to mildly elevated albuminuria, with an ACR less than 30 mg/g. Patients with
albuminuria in this category (A1) should have a goal blood pressure of less than 140/90
mm Hg (Answer B is correct).
A goal blood pressure of less than 130/80 mm Hg would be desired for a patient with
moderate to severe (category A2) albuminuria (Answer A is incorrect). Answer C is
incorrect because the diastolic blood pressure goal is too low (80 mm Hg). Answer D is
incorrect because the systolic blood pressure goal is too low (130 mm Hg).
✔✔A 66/M has an eGFR of 55. His albumin/creatinine ratio is 100 mg/g. His Hgb is
currently 13.2 g/dL, with normal RBC indices without treatment. Which best reflects the
recommended minimum frequency of Hgb monitoring in this patient?
