MCCQE Part I Nephrology Questions: 10 Free Practice MCQs

Ten MCCQE Part I-style nephrology questions with the answer and the reasoning behind it. They come from the CA.med bank, which has 19 nephrology questions and many more across every topic.

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1. 1 / 10

   A 66-year-old man with acute kidney injury is anuric. His serum potassium is 7.1 mmol/L, his arterial pH is 7.12, and he has bilateral crackles with hypoxaemia from pulmonary oedema despite oxygen and intravenous diuretics.

   Which step is most appropriate now?

   • A. Repeat the potassium and creatinine in six hours
   • B. Give a further dose of a loop diuretic and reassess in 12 hours
   • C. Wait to begin renal replacement therapy until the creatinine exceeds 500 umol/L
   • D. Start renal replacement therapy without delay
   Show answer

   Answer: D. Start renal replacement therapy without delay

   Why: KDIGO advises that renal replacement therapy be initiated emergently when life-threatening changes in fluid, electrolyte, and acid-base balance exist. Severe hyperkalaemia, severe acidosis, pulmonary oedema, and uraemic complications are recognised emergent indications, and this patient has at least three of them. Watchful waiting for repeat blood work, further diuresis, or an arbitrary creatinine threshold all delay treatment that is needed at once.

   • A. Deferring treatment to repeat blood work leaves severe hyperkalaemia and acidaemia untreated, and timing follows the clinical picture and trends rather than laboratory values alone.
   • B. Diuretics have already failed to control the pulmonary oedema, so continuing medical therapy delays the treatment this presentation requires.
   • C. There is no creatinine threshold that must be reached before dialysis, and volume overload, solute imbalance, and acidaemia drive the decision.

   Sources: KDIGO 2012 Clinical Practice Guideline for Acute Kidney Injury

2. 2 / 10

   A 74-year-old woman with chronic kidney disease stage 4 has a haemoglobin of 112 g/L. She feels well, with no fatigue or breathlessness, and has no other symptom of anaemia. Her iron studies are normal.

   According to Choosing Wisely Canada nephrology recommendations, what is the most appropriate action?

   • A. Transfuse two units of red blood cells now
   • B. Repeat the haemoglobin in one week and start an erythropoiesis-stimulating agent if it falls below 110 g/L
   • C. Start an erythropoiesis-stimulating agent aiming for a haemoglobin above 130 g/L
   • D. Do not start an erythropoiesis-stimulating agent at this time
   Show answer

   Answer: D. Do not start an erythropoiesis-stimulating agent at this time

   Why: Choosing Wisely Canada, through the Canadian Society of Nephrology, recommends that erythropoiesis-stimulating agents not be started in chronic kidney disease when the haemoglobin is 100 g/L or greater and there are no symptoms of anaemia. Administering these agents with the aim of normalising haemoglobin has not shown a survival or cardiovascular benefit and may be harmful compared with a more conservative approach. This patient has a haemoglobin of 112 g/L and is asymptomatic, so no agent is indicated.

   • A. Red cell transfusion is not indicated in a well patient with a haemoglobin of 112 g/L and no symptoms of anaemia.
   • B. The threshold in the recommendation is a haemoglobin of 100 g/L, and a value of 112 g/L without symptoms does not justify starting treatment.
   • C. Attempts to normalise haemoglobin have not improved survival or cardiovascular outcomes and may cause harm, so a target above 130 g/L is not advised.

   Sources: Choosing Wisely Canada, Nephrology Recommendations (Canadian Society of Nephrology)

3. 3 / 10

   A 61-year-old man has an eGFR of 42 mL/min per 1.73 m2 and a urine albumin-to-creatinine ratio of 18 mg/mmol on two occasions four months apart. He feels well, and a repeat urinalysis shows no cells or casts.

   Which conclusion is best supported?

   • A. The low eGFR and the albuminuria together indicate acute kidney injury rather than a chronic process
   • B. Albuminuria is not abnormal until the ratio exceeds 30 mg/mmol
   • C. One set of abnormal results would have been enough to make the diagnosis
   • D. The findings indicate chronic kidney disease because both abnormalities have persisted for more than three months
   Show answer

   Answer: D. The findings indicate chronic kidney disease because both abnormalities have persisted for more than three months

   Why: Chronic kidney disease is defined as abnormalities of kidney structure or function present for a minimum of three months with implications for health, and it is diagnosed when the eGFR or the urine albumin-to-creatinine ratio is abnormal and persistent. This man has both a reduced eGFR and an elevated albumin-to-creatinine ratio that have persisted for four months. A single abnormal result is not sufficient, an acute process would not have lasted this long, and the albuminuria threshold is 3.0 mg/mmol rather than 30 mg/mmol.

   • A. Both abnormalities have been present for four months, which indicates a chronic rather than an acute process.
   • B. A urine albumin-to-creatinine ratio of 3.0 mg/mmol or more on serial testing is abnormal, so a value of 18 mg/mmol is well above the threshold.
   • C. A single isolated abnormal measurement does not establish the diagnosis, because the abnormalities must persist for at least three months.

   Sources: BC Guidelines (BC Ministry of Health), Chronic Kidney Disease: Diagnosis and Management (2025); KDIGO 2024 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease

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5. 4 / 10

   A 34-year-old man presents to the ED with sudden onset severe right flank pain radiating to the right groin, accompanied by nausea. He is afebrile. Vital signs are stable. Urinalysis shows haematuria (3+), no pyuria, no nitrites. He has no prior history of kidney stones. Creatinine is 84 µmol/L.

   What is the most appropriate next investigation to confirm the diagnosis?

   • A. Plain abdominal X-ray (KUB) as the only imaging
   • B. Intravenous pyelogram (IVP) with contrast
   • C. Non-contrast CT scan of the abdomen and pelvis (NCCT-KUB)
   • D. Renal ultrasound only
   Show answer

   Answer: C. Non-contrast CT scan of the abdomen and pelvis (NCCT-KUB)

   Why: Acute renal colic management: (1) NCCT-KUB confirms diagnosis; (2) IV ketorolac (30 mg) or oral NSAIDs for pain (superior to opioids for renal colic); (3) Alpha-blockers (tamsulosin 0.4 mg) may facilitate passage of distal ureteral stones ≤10 mm; (4) Emergency urological intervention if obstruction with infected urine (sepsis), solitary kidney, bilateral obstruction, or persistent vomiting. Metabolic workup (24-hour urine, serum calcium, uric acid) after first stone to identify modifiable risk factors.

   • A. KUB has poor sensitivity (45-58%), it misses uric acid, cystine, and small stones. It is not the standard first-line imaging in Canadian ED practice.
   • B. IVP has been largely replaced by NCCT in most Canadian centres, it requires IV contrast (nephrotoxic risk), takes longer, and has lower sensitivity than NCCT for stone detection.
   • D. Ultrasound is a reasonable first-line test in pregnant patients and children to avoid radiation, but has lower sensitivity (45-67%) for ureteral calculi. NCCT is preferred when definitive diagnosis and location are needed in a non-pregnant adult.

   Sources: CUA (Canadian Urological Association) Nephrolithiasis Guidelines 2016; Choosing Wisely Canada, Emergency Medicine

6. 5 / 10

   A 74-year-old man with CKD stage 3b (eGFR 32 mL/min/1.73 m²) and diabetes requires a CT coronary angiogram with contrast. His creatinine is 172 µmol/L. He is euvolaemic. His current medications include metformin 1000 mg BID.

   What is the most important pre-procedure measure to prevent contrast-induced nephropathy (CIN)?

   • A. Administer N-acetylcysteine (NAC) 1200 mg BID starting the day before the procedure
   • B. IV 0.9% normal saline hydration (1 mL/kg/hr for 3-12 hours before and after procedure) and hold metformin 48 hours post-contrast
   • C. Administer furosemide prior to contrast to increase urine flow
   • D. Sodium bicarbonate infusion is superior to normal saline in all patients, and metformin can be continued
   Show answer

   Answer: B. IV 0.9% normal saline hydration (1 mL/kg/hr for 3-12 hours before and after procedure) and hold metformin 48 hours post-contrast

   Why: CIN risk factors: CKD (eGFR <45 most significant), diabetes mellitus, volume depletion, nephrotoxic drugs, large contrast volume, isosmolar/high osmolar contrast (use iso-osmolar or low-osmolar iodinated contrast). Prevention: IV NS 1 mL/kg/hr pre and post; use minimum contrast volume; avoid repeat exposures within 24-48h; hold metformin pre/post-procedure. NAC and sodium bicarbonate are no longer routinely recommended (PRESERVE trial). Post-procedure: check creatinine at 48 hours in high-risk patients.

   • A. Multiple large RCTs (PRESERVE trial) have shown NAC does not reduce the incidence of AKI or mortality after contrast exposure. It is no longer recommended as routine prophylaxis by Canadian or international guidelines.
   • C. Loop diuretics cause volume depletion, concentrating contrast in renal tubules, they INCREASE CIN risk and are contraindicated as prophylaxis. Only the RenalGuard system (forced diuresis with matched hydration) has shown benefit in very specific settings.
   • D. The PRESERVE trial (NEJM 2018) found sodium bicarbonate is not superior to isotonic saline for CIN prevention. Isotonic NS is the standard; sodium bicarbonate may be used as an acceptable alternative but is not proven superior.

   Sources: PRESERVE Trial (NEJM 2018); Canadian Society of Nephrology recommendations on CIN prevention

7. 6 / 10

   A 68-year-old man with chronic kidney disease has an eGFR of 12 mL/min per 1.73 m2. He has no oedema, nausea, or anorexia, and his serum potassium and bicarbonate are normal. He and his family have discussed his goals with the nephrology team.

   What is the most appropriate plan?

   • A. Begin haemodialysis this week because the eGFR is below 15 mL/min per 1.73 m2
   • B. Continue close nephrology follow-up and defer dialysis until symptoms or another indication appear
   • C. Begin peritoneal dialysis this week
   • D. Stop nephrology follow-up until the eGFR falls below 6 mL/min per 1.73 m2 or symptoms start
   Show answer

   Answer: B. Continue close nephrology follow-up and defer dialysis until symptoms or another indication appear

   Why: Choosing Wisely Canada advises against initiating chronic dialysis without a shared decision-making process, and notes that recent Canadian Society of Nephrology guidance recommends close nephrology follow-up for patients with an eGFR below 15 mL/min per 1.73 m2, with dialysis deferred until symptoms of uraemia, volume overload, hyperkalaemia, or acidosis become an issue or the eGFR falls below 6 mL/min per 1.73 m2. He is asymptomatic with normal potassium and bicarbonate, so dialysis is not yet indicated, but follow-up must continue.

   • A. An eGFR below 15 mL/min per 1.73 m2 alone is not an indication to start dialysis, and starting before symptoms or another clinical indication adds burden without benefit.
   • C. Peritoneal dialysis is not started on the basis of a low eGFR alone, and the timing should follow symptoms, fluid status, and biochemical indications.
   • D. Close follow-up is specifically recommended at this eGFR, so withdrawing follow-up would risk missing the development of an indication for treatment.

   Sources: Choosing Wisely Canada, Nephrology Recommendations (Canadian Society of Nephrology)

8. 7 / 10

   An 82-year-old woman living in a long-term care home has a urine culture that grows Escherichia coli. She has no fever, no dysuria, no suprapubic discomfort, and no change in her usual urinary pattern. She is otherwise stable.

   What is the most appropriate management?

   • A. Give a seven-day course of an antimicrobial
   • B. Do not give antimicrobial therapy for the bacteriuria
   • C. Repeat the urine culture to confirm the result before deciding
   • D. Treat only if the colony count exceeds 100,000 per mL
   Show answer

   Answer: B. Do not give antimicrobial therapy for the bacteriuria

   Why: Choosing Wisely Canada urology recommendations advise against using antimicrobials to treat asymptomatic bacteriuria in the elderly, because studies show no significant risk of morbidity when it is left untreated and increased adverse antimicrobial effects when it is treated. Symptoms, rather than a positive culture, define urinary tract infection. Screening for and treating asymptomatic bacteriuria is recommended before urologic procedures in which mucosal bleeding is anticipated, which does not apply to this woman.

   • A. Treating asymptomatic bacteriuria in older adults has not shown benefit and is associated with increased adverse antimicrobial effects.
   • C. Confirmatory repeat testing does not change the management of asymptomatic bacteriuria, which is not treated.
   • D. The clinical definition of urinary tract infection rests on symptoms, and a colony count threshold alone does not justify treatment.

   Sources: Choosing Wisely Canada, Urology Recommendations (Canadian Urological Association)

9. 8 / 10

   A 44-year-old woman has oliguria and a rising creatinine. Her urine osmolality is 620 mosmol/kg and her urine sodium is 8 mmol/L. Urine output is 0.3 mL/kg per hour. She has no history of volume loss and has taken no nephrotoxic drugs.

   How should these urine findings be interpreted?

   • A. They confirm that the cause is pre-renal and that fluids alone will correct it, so no further work up is needed
   • B. They indicate established tubular necrosis with loss of concentrating ability
   • C. They indicate intact tubular function, which does not exclude intrinsic kidney disease such as glomerulonephritis
   • D. They cannot be interpreted because urine sodium is unreliable during oliguria
   Show answer

   Answer: C. They indicate intact tubular function, which does not exclude intrinsic kidney disease such as glomerulonephritis

   Why: KDIGO notes that a high urine osmolality with a low urine sodium during oliguria and azotaemia is strong evidence of intact tubular function, but warns that this should not be read as benign or purely pre-renal, because intact tubular function early in the course may occur in glomerulonephritis and other intrinsic diseases. The urine indices therefore inform, but do not settle, the pre-renal versus intrinsic question, and fluid alone is not guaranteed to correct the abnormality.

   • A. Intact tubular function can accompany early intrinsic kidney disease such as glomerulonephritis, so these values do not prove that the process is pre-renal or reversible with fluid.
   • B. Injured tubules lose concentrating ability, so a high urine osmolality with a low urine sodium argues against established tubular necrosis.
   • D. Urine indices remain interpretable during oliguria, and automatically classifying such results as pre-renal can lead to incorrect management decisions.

   Sources: KDIGO 2012 Clinical Practice Guideline for Acute Kidney Injury

10. 9 / 10

    A 5-year-old boy presents with 1 week of periorbital oedema, worse in the mornings, and bilateral pitting leg oedema. Parents note his urine has been foamy. No haematuria. BP 95/62 mmHg. Labs: serum albumin 14 g/L, total protein 38 g/L, urine protein:creatinine ratio 450 mg/mmol, normal creatinine, normal complement C3/C4.

    What is the most likely diagnosis and first-line treatment?

    • A. Nephritic syndrome due to post-streptococcal glomerulonephritis; supportive care
    • B. Focal segmental glomerulosclerosis; cyclosporine
    • C. Congestive heart failure; diuretics and ACE inhibitor
    • D. Nephrotic syndrome due to minimal change disease; oral prednisolone
    Show answer

    Answer: D. Nephrotic syndrome due to minimal change disease; oral prednisolone

    Why: Paediatric nephrotic syndrome criteria: proteinuria ≥40 mg/m²/h (urine P:Cr >200-400 mg/mmol), hypoalbuminaemia (<25 g/L), oedema, hyperlipidaemia. In children 2-10 years with typical nephrotic syndrome and no red flags (haematuria, hypertension, low complement, renal impairment), an empirical trial of prednisolone is standard without biopsy. ISKDC protocol: prednisolone 60 mg/m²/day for 4-6 weeks + 40 mg/m² alternate days for 4-6 weeks. Minimal change disease: ~90% remission with steroids. Complications: infection (peritonitis, S. pneumoniae, E. coli), thromboembolism, hyperlipidaemia. Penicillin prophylaxis and pneumococcal vaccine recommended.

    • A. Nephritic syndrome presents with haematuria, hypertension, and low complement C3. This child has nephrotic syndrome features (massive proteinuria, hypoalbuminaemia, oedema, no haematuria, normal complement), inconsistent with PSGN.
    • B. FSGS is less common in young children and typically presents when steroid-resistant nephrotic syndrome prompts biopsy. Initial treatment is still prednisolone; cyclosporine is for steroid-resistant cases.
    • C. Heart failure would present with elevated JVP, cardiomegaly, and respiratory symptoms. Periorbital oedema that is worse in the morning, massive proteinuria, and hypoalbuminaemia are hallmarks of nephrotic syndrome.

    Sources: ISKDC Guidelines; CPS Position Statement: Nephrotic Syndrome in Children (2020)

11. 10 / 10

    A 70-year-old woman has a stable eGFR of 27 mL/min per 1.73 m2 and a urine albumin-to-creatinine ratio of 12 mg/mmol. Her kidney function has changed little over the past year and she feels well.

    According to British Columbia guidance, what is the most appropriate action?

    • A. Urgent same-day discussion with a nephrologist
    • B. Priority referral to a nephrologist
    • C. Continue follow-up in primary care with repeat testing in one year
    • D. Referral to urology for assessment of the urinary tract
    Show answer

    Answer: B. Priority referral to a nephrologist

    Why: The British Columbia guidelines separate urgent from priority referral. Urgent referral is triggered by findings such as an active urine sediment, unexplained acute kidney injury, an abrupt sustained fall in eGFR, an eGFR below 15 mL/min per 1.73 m2, or nephrotic syndrome. Priority referral is triggered by an eGFR below 30 mL/min per 1.73 m2, an unexplained persistent albumin-to-creatinine ratio above 30 to 70 mg/mmol, or progressive disease. This woman falls into the priority group.

    • A. Urgent discussion is reserved for problems such as a sustained abrupt fall in eGFR, active urine sediment, or an eGFR below 15 mL/min per 1.73 m2, none of which is present.
    • C. A stable eGFR of 27 mL/min per 1.73 m2 needs specialist input, and annual primary care follow-up alone does not meet the recommended threshold for referral.
    • D. Urology is more appropriate for problems such as a kidney mass, gross haematuria, obstruction, or a large symptomatic stone, and none of these is described.

    Sources: BC Guidelines (BC Ministry of Health), Chronic Kidney Disease: Diagnosis and Management (2025)

Exam-style questions written by MedHub for practice. They are not official exam questions.