ABIM Nephrology Initial Certification Examination Practice Test
Nephrology centers on disorders of kidney function, glomerular and tubular disease, electrolyte and acid-base disturbances, and complications of chronic kidney failure. These practice cases use laboratory patterns, urine findings, biopsy features, and clinical context to distinguish renal causes of illness and select appropriate diagnostic or management steps.
Exam overview
About the ABIM Nephrology Initial Certification Examination Exam
Clinical reasoning in nephrology requires connecting serum chemistry and urine studies with kidney physiology. Cases may test recognition of acute tubular injury, glomerular bleeding, immune-complex disease, renal tubular acidosis, and disturbances in potassium or bicarbonate. Interpretation of urine sediment, proteinuria, urine pH, and kidney biopsy findings helps localize disease and narrow the differential. Decisions also involve assessing whether an abnormal laboratory result is genuine, addressing complications such as uremic pruritus, and responding to dialysis-related infection. Work through each presentation by identifying the affected renal compartment, checking whether the findings fit a coherent physiologic mechanism, and distinguishing immediate evaluation from longer-term management.
Sample Practice Questions
Review a selection from this exam's published US Practice Tests practice bank.
A 63-year-old woman with chronic kidney disease has persistent serum bicarbonate of 18 mEq/L, normal anion gap, and no acute illness. Which acid-base process most likely accounts for this finding?
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Correct answer: BAs kidney function declines, reduced ammonium production and net acid excretion can lead to chronic metabolic acidosis, commonly with a normal anion gap in earlier stages. Evaluation should consider other causes, and alkali therapy may be considered based on the clinical context and degree of acidosis.
A 49-year-old woman has episodic muscle weakness. Her serum potassium is 2.8 mEq/L, bicarbonate is 31 mEq/L, and blood pressure is 112/70 mm Hg. She reports frequent use of an over-the-counter herbal laxative. Which mechanism most likely contributes to her electrolyte and acid-base findings?
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Correct answer: ALaxative-associated gastrointestinal losses can cause volume depletion and chloride depletion. The resulting secondary aldosterone response promotes renal potassium and hydrogen ion loss, contributing to hypokalemic metabolic alkalosis. The history should prompt assessment for ongoing gastrointestinal losses and related complications.
A 58-year-old man with chronic kidney disease has a serum potassium of 5.5 mEq/L on repeated outpatient testing. He is asymptomatic, and his ECG is unchanged. Which initial step best helps determine whether the result represents true hyperkalemia?
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Correct answer: APseudohyperkalemia from hemolysis or other sample-related factors should be considered, particularly when an unexpected result is not accompanied by symptoms or ECG changes. A prompt repeat measurement with careful collection helps confirm the potassium level before treatment decisions, while clinical urgency and ECG findings still guide immediate care.
A 46-year-old man has recurrent calcium phosphate stones. Serum calcium is normal, urine pH is persistently 6.5, and serum bicarbonate is 18 mEq/L with a normal anion gap. Which disorder best explains this pattern?
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Correct answer: ADistal renal tubular acidosis impairs distal urinary acidification, producing a normal-anion-gap metabolic acidosis with inappropriately alkaline urine. It is associated with calcium phosphate stones and nephrocalcinosis.
A 64-year-old man with long-standing diabetes has a urine sediment containing muddy brown granular casts after several days of hypotension during surgery. Which kidney injury is most likely?
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Correct answer: AMuddy brown granular casts are characteristic of acute tubular injury, commonly following ischemia or nephrotoxic exposure. The sediment helps distinguish tubular injury from glomerular or interstitial processes.
A 30-year-old man has persistent microscopic hematuria detected on several routine urine tests. He feels well, has normal blood pressure and kidney function, and has no proteinuria. Urine microscopy shows dysmorphic erythrocytes. Which source of bleeding is most likely?
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Correct answer: ADysmorphic erythrocytes, particularly when identified in an appropriate clinical setting, favor glomerular bleeding because red cells become distorted while passing through the glomerular filtration barrier and nephron. Evaluation still depends on clinical context, but this sediment finding points to a glomerular source.
A patient with end-stage kidney disease receiving hemodialysis develops fever and rigors shortly after dialysis begins. The tunneled catheter exit site is mildly erythematous. Which initial approach is most appropriate?
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Correct answer: AFever and rigors during dialysis in a patient with a catheter raise concern for catheter-related bloodstream infection. Obtain appropriate blood cultures promptly and start empiric therapy tailored to local practice and illness severity; catheter management depends on the organism, severity, and response.
How to use this practice test
Access is free. The question bank contains 50 nephrology practice questions; each session presents up to 20 questions selected at random. Results appear after the session, allowing you to identify which clinical patterns or renal mechanisms need further review.
Preparation tips
- For acid-base cases, calculate the anion gap and compare serum bicarbonate, potassium, urine pH, and stone composition to distinguish renal tubular disorders.
- Practice localizing hematuria and kidney injury using urine microscopy, including dysmorphic erythrocytes and granular casts, alongside proteinuria and kidney function.
- For suspected hyperkalemia, consider repeat sampling and potential specimen-related artifacts before attributing an isolated result to a physiologic change.
- Review how biopsy findings—such as immune deposits and their location—support classification of glomerular disease, including lupus nephritis and membranous nephropathy.
- For dialysis-associated fever, connect timing and access-site findings to catheter-related bloodstream infection and the need for prompt evaluation.