100+ Free ABIM Nephrology Practice Questions

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Question 1

Score: 0/0

A 68-year-old man hospitalized for pneumonia has a serum creatinine rise from 0.9 mg/dL (baseline) to 1.6 mg/dL over 36 hours with urine output of 0.4 mL/kg/hr for 8 hours. By KDIGO criteria, this represents which AKI stage?

No AKI — changes are within normal variation

AKI stage 1

AKI stage 2

AKI stage 3

to track

2026 Statistics

Key Facts: ABIM Nephrology Exam

~$2,990

ABIM Nephrology Exam Fee

ABIM 2026

~240 MCQs

Exam Length

4 modules, ~10 hr day

24 months

Nephrology Fellowship

ACGME-accredited

Annual

Exam Frequency

Offered each fall

80-90%

First-Time Pass Rate

ABIM historical

SGLT2i + ACEi/ARB + MRA

CKD Backbone

KDIGO 2024

Nephrology is one of the core ABIM subspecialties, feeding roughly 400-500 new fellowship graduates per year into a workforce managing over 800,000 US patients with ESKD and tens of millions with CKD. The 2026 exam emphasizes KDIGO 2022/2024 guidelines, SGLT2 inhibitors (dapagliflozin DAPA-CKD, empagliflozin EMPA-KIDNEY — both indicated regardless of diabetes status) and nonsteroidal MRA finerenone (FIDELIO-DKD, FIGARO-DKD) as the new standard backbone in CKD with albuminuria. IgA nephropathy has been transformed by targeted-release budesonide (Nefecon, NefIgArd) and sparsentan (2023 FDA approval), while hepatorenal syndrome is now managed with albumin + terlipressin (2022 FDA). Transplant content centers on the 2014 allocation revision, KDPI, tacrolimus + MMF + prednisone maintenance, BK virus nephropathy, and Banff cellular/antibody-mediated rejection grading. Board-certified nephrologists earn a median of $280K-$350K with additional income from dialysis medical directorships.

Sample ABIM Nephrology Practice Questions

Try these sample questions to test your ABIM Nephrology exam readiness. Each question includes a detailed explanation. Start the interactive quiz above for the full 100+ question experience with AI tutoring.

1A 68-year-old man hospitalized for pneumonia has a serum creatinine rise from 0.9 mg/dL (baseline) to 1.6 mg/dL over 36 hours with urine output of 0.4 mL/kg/hr for 8 hours. By KDIGO criteria, this represents which AKI stage?

A.No AKI — changes are within normal variation

B.AKI stage 1

C.AKI stage 2

D.AKI stage 3

Explanation: KDIGO AKI stage 1 = Cr increase >=0.3 mg/dL in 48 h OR >=1.5-1.9x baseline in 7 days, OR UOP <0.5 mL/kg/hr for 6-12 hours. A Cr of 1.6 from baseline 0.9 is 1.78x (stage 1 by creatinine) and UOP 0.4 mL/kg/hr for 8 hours also meets stage 1 by urine output. Stage 2 requires 2.0-2.9x Cr or UOP <0.5 for >=12 hr; stage 3 requires >=3.0x, Cr >=4.0, dialysis, or UOP <0.3 for >=24 hr (or anuria >=12 hr).

2A patient with heart failure on furosemide 80 mg BID develops AKI. FENa is 0.8%. Which index is most useful to evaluate pre-renal vs ATN in this setting?

A.FENa remains the gold standard regardless of diuretics

B.FEUrea, with <35% suggesting pre-renal

C.Urine osmolality — values <300 confirm pre-renal

D.Urinary sodium alone

Explanation: Diuretics cause natriuresis and falsely elevate FENa — FENa can be misleading in patients on loop or thiazide diuretics. FEUrea is more reliable on diuretics: <35% suggests pre-renal AKI, while >50% favors ATN. Urea is reabsorbed proximally (not affected by loop/thiazide action in the distal nephron).

3A 72-year-old on trimethoprim-sulfamethoxazole for cellulitis develops AKI on day 10 with low-grade fever, rash, eosinophilia, and sterile pyuria. Urine microscopy shows WBC casts. Which is the most likely diagnosis?

A.Acute tubular necrosis

B.Allergic interstitial nephritis (AIN)

C.Pyelonephritis

D.Crystalline nephropathy

Explanation: Classic AIN triad — fever, rash, eosinophilia — is actually present in only ~10% of cases, but WBC casts, sterile pyuria, and a plausible offending drug (Bactrim, PPIs, NSAIDs, beta-lactams) strongly suggest AIN. Eosinophiluria is sensitive but not specific (also seen in atheroembolic disease). Definitive diagnosis is kidney biopsy showing interstitial lymphocytic infiltrate. Treatment: stop the offending drug ± corticosteroids.

4Which urinary finding is most specific for acute tubular necrosis (ATN)?

A.WBC casts

B.RBC casts

C.Muddy brown / pigmented granular casts and renal tubular epithelial cell casts

D.Hyaline casts

Explanation: Muddy brown (pigmented coarse granular) casts and renal tubular epithelial (RTE) cell casts are the classic sediment findings of ATN, reflecting sloughed tubular cells and debris. WBC casts = pyelonephritis/AIN. RBC casts = glomerulonephritis. Hyaline casts = normal or pre-renal.

5A 55-year-old undergoes cardiac catheterization with iodinated contrast. What is the most effective strategy to prevent contrast-induced AKI?

A.Oral N-acetylcysteine 1200 mg BID for 2 days

B.IV isotonic crystalloid peri-procedurally

C.Prophylactic hemodialysis immediately after contrast

D.Sodium bicarbonate infusion rather than normal saline

Explanation: IV isotonic crystalloid (normal saline or LR) before and after contrast is the only consistently beneficial intervention. The PRESERVE trial (2018) showed IV sodium bicarbonate is no better than saline and IV NAC is no better than placebo. Peri-procedural hydration remains the cornerstone, along with minimizing contrast volume and holding nephrotoxins.

6A 34-year-old found unconscious after crush injury has CK 85,000, K 6.8, Cr 3.4. Urine dipstick is 3+ for blood but microscopy shows no RBCs. What is the most appropriate initial management?

A.Aggressive IV crystalloid targeting UOP 200-300 mL/hr

B.Urgent emergent dialysis before volume repletion

C.IV sodium bicarbonate bolus without IVF

D.Mannitol and loop diuretic to induce diuresis

Explanation: Rhabdomyolysis-induced AKI is treated with aggressive IV crystalloid (normal saline or LR) to maintain UOP 200-300 mL/hr, which dilutes tubular myoglobin and reduces cast formation. Urine dipstick is positive for blood from myoglobin, but microscopy shows no RBCs (pseudohematuria). Mannitol and loops lack evidence. Bicarbonate alkalinization (urine pH >6.5) is historically used but not clearly superior to volume alone. Dialysis is for established AKI with refractory hyperkalemia, acidosis, volume overload, or uremia.

7A patient with cirrhosis, ascites, and baseline Cr 0.9 is admitted with SBP. Cr rises to 2.8 despite 48 hours of albumin 1 g/kg and diuretic withdrawal. Urine Na is 8 mEq/L and urinalysis is bland. Which is the most appropriate next step?

A.Terlipressin plus albumin

B.Loop diuretic challenge

C.Renal artery Doppler ultrasound

D.Empiric IV vancomycin

Explanation: This is hepatorenal syndrome type 1 (HRS-AKI) — rapid Cr rise in cirrhosis/ascites, bland urine, low urine Na, failure to respond to albumin + diuretic withdrawal. The FDA approved terlipressin + albumin in September 2022 (CONFIRM trial) for HRS-1 in the US; it reverses HRS in ~30-40% of patients. Alternatives include norepinephrine + albumin or midodrine + octreotide + albumin. Definitive therapy is liver transplantation.

8A 60-year-old with type 2 diabetes, HTN, and Cr 1.4 (eGFR 52) with UACR 280 mg/g is on maximal ACEi. Which additional therapy has class I evidence to slow CKD progression?

A.Dapagliflozin or empagliflozin (SGLT2 inhibitor)

B.Potassium citrate supplementation

C.Allopurinol 300 mg daily

D.Atorvastatin 80 mg

Explanation: SGLT2 inhibitors dapagliflozin (DAPA-CKD) and empagliflozin (EMPA-KIDNEY) showed reduction in CKD progression, cardiovascular death, and hospitalization for heart failure regardless of diabetes status. KDIGO 2022/2024 and ADA recommend SGLT2i in CKD with eGFR >=20-25 and UACR >=200 mg/g (also eGFR >=20 for empagliflozin). This is now standard second-line after ACEi/ARB in CKD with albuminuria.

9In CKD stage 3b (eGFR 35) with diabetic nephropathy and UACR 400 on ACEi and SGLT2i, which agent has additional renal/CV benefit per FIDELIO-DKD and FIGARO-DKD?

A.Finerenone (nonsteroidal MRA)

B.Spironolactone

C.Eplerenone

D.Amiloride

Explanation: Finerenone is a nonsteroidal, selective mineralocorticoid receptor antagonist. FIDELIO-DKD and FIGARO-DKD (combined FIDELITY analysis) demonstrated reductions in CKD progression and cardiovascular events in type 2 diabetes with CKD. KDIGO 2022 gives a 2A recommendation. It has less hyperkalemia than spironolactone, but potassium monitoring is still required. Initiate only if K <=4.8 mEq/L.

10A dialysis patient has calcium 9.2, phosphorus 6.8, PTH 780 (high). Which is the most appropriate addition?

A.Non-calcium-based phosphate binder (sevelamer or lanthanum)

B.Calcium carbonate 1500 mg with meals

C.Activated vitamin D (calcitriol) alone

D.Thiazide diuretic

Explanation: Elevated phosphorus with normal-high calcium in CKD-MBD is best managed with a non-calcium binder (sevelamer carbonate, lanthanum carbonate, ferric citrate, sucroferric oxyhydroxide) to avoid further calcium loading and vascular calcification. Calcium-based binders increase the calcium-phosphate product and promote calciphylaxis. Activated vitamin D alone raises Ca and P and worsens hyperphosphatemia.

About the ABIM Nephrology Exam

The ABIM Nephrology subspecialty exam certifies internists who have completed a 24-month ACGME-accredited nephrology fellowship. It covers chronic kidney disease (CKD) staging and management, CKD-MBD, acute kidney injury (AKI) by KDIGO criteria, glomerular diseases, dialysis (HD, PD, CRRT), kidney transplantation and immunosuppression, electrolyte and acid-base disorders, hypertension, kidney stones, and nephrology in special populations including pregnancy and the critically ill.

Questions

240 scored questions

Time Limit

~10-hour exam day (four ~2-hour modules)

Passing Score

Criterion-referenced scaled score (pass/fail; specific cut not published)

Exam Fee

~$2,990 application + exam fee (American Board of Internal Medicine (ABIM))

ABIM Nephrology Exam Content Outline

22%

Chronic Kidney Disease and CKD-MBD

KDIGO GFR G1-G5 and albuminuria A1-A3 staging, CKD-MBD (calcium, phosphorus, PTH, vitamin D, FGF-23), secondary and tertiary hyperparathyroidism with cinacalcet/etelcalcetide and paricalcitol, non-calcium phosphate binders (sevelamer, lanthanum, ferric citrate, sucroferric oxyhydroxide), anemia with ESAs (darbepoetin) and IV iron, ACEi/ARB, SGLT2i (DAPA-CKD, EMPA-KIDNEY), finerenone (FIDELIO-DKD, FIGARO-DKD).

18%

Acute Kidney Injury

KDIGO AKI stages 1/2/3 by creatinine and urine output criteria, pre-renal vs intrinsic vs post-renal, urine indices (FENa and FEUrea when on diuretics), ATN vs AIN (eosinophils, WBC casts, muddy brown casts), rhabdomyolysis, contrast-induced nephropathy prevention (IV crystalloid, limited value of NAC), hepatorenal syndrome type 1/2 with albumin + terlipressin (2022 FDA), cardiorenal syndrome.

18%

Glomerular Diseases

Nephrotic: MCD (steroid-responsive), FSGS (primary vs secondary, APOL1 in Black patients), membranous nephropathy (PLA2R Ab, rituximab), diabetic nephropathy. Nephritic: IgA nephropathy (sparsentan, targeted-release budesonide Tarpeyo NefIgArd 2023), PIGN, MPGN, ANCA vasculitis GPA/MPA (RAVE — rituximab or cyclophosphamide), anti-GBM (PLEX + cyclo + steroids), lupus nephritis class III/IV (IV cyclophosphamide or MMF + belimumab or voclosporin), HSP, amyloid (AL — dara-CyBorD), cryoglobulinemia (hep C — DAA + rituximab).

14%

Dialysis and Renal Replacement Therapy

Hemodialysis access (AVF > AVG > tunneled catheter), Kt/V targets, ultrafiltration, dialysis-related amyloidosis. Peritoneal dialysis (CAPD vs APD), peritonitis (coag-negative staph most common), exit site care. Continuous renal replacement therapy (CVVHDF) in ICU, timing of initiation (AKIKI, STARRT-AKI — watchful waiting often acceptable), tolvaptan for rapidly progressive ADPKD (REPRISE).

10%

Kidney Transplantation

2014 allocation system revision, KDPI, deceased vs living donor (living preferred), induction (basiliximab vs ATG in high-risk), maintenance (tacrolimus + MMF + prednisone taper), acute rejection — cellular (Banff grade 1-3) vs antibody-mediated (C4d staining, DSA), BK virus nephropathy, CMV prophylaxis, EBV-driven PTLD, delayed graft function, recurrent original disease, post-transplant SCC skin cancer.

12%

Fluid, Electrolyte, and Acid-Base Disorders

Hyponatremia classification by tonicity and volume, SIADH, cerebral salt wasting, DI (central vs nephrogenic lithium-induced), hypernatremia. Potassium: pseudohyperkalemia, hyperkalemia treatment (Ca gluconate, insulin+D50, albuterol, patiromer, ZS-9), hypokalemia. Calcium/magnesium/phosphorus. Anion gap (MUDPILES), osmolar gap (methanol, ethylene glycol), Winter's formula, RTAs I/II/IV, toxic alcohols (fomepizole + HD).

Hypertension, Stones, and Special Populations

Renovascular hypertension (FMD vs atherosclerotic RAS, CORAL trial), primary aldosteronism (aldo:renin ratio >30, saline or captopril suppression, adrenal vein sampling, spironolactone). Kidney stones (24-hr urine — Ca, citrate, oxalate, uric acid, cystine, Na), calcium oxalate (80%), struvite, uric acid, cystinuria. Pregnancy (preeclampsia, HELLP, acute fatty liver), geriatric kidney, UTI.

How to Pass the ABIM Nephrology Exam

What You Need to Know

Passing score: Criterion-referenced scaled score (pass/fail; specific cut not published)
Exam length: 240 questions
Time limit: ~10-hour exam day (four ~2-hour modules)
Exam fee: ~$2,990 application + exam fee

Keys to Passing

Complete 500+ practice questions
Score 80%+ consistently before scheduling
Focus on highest-weighted sections
Use our AI tutor for tough concepts

ABIM Nephrology Study Tips from Top Performers

1Master KDIGO CKD staging cold: the G1-G5 GFR categories crossed with A1-A3 albuminuria categories create the risk heatmap. Every CKD management question keys off of stage. Know SGLT2i (dapagliflozin, empagliflozin) are indicated in CKD regardless of diabetes (DAPA-CKD eGFR >=25, EMPA-KIDNEY >=20), and finerenone (FIDELIO/FIGARO-DKD) is added on ACEi/ARB for diabetic CKD with albuminuria.

2For AKI, memorize KDIGO stages (stage 1: Cr >=1.5x baseline or UOP <0.5 mL/kg/hr x 6-12h; stage 3: Cr >=3x or dialysis). Learn urine indices: FENa <1% = pre-renal, >2% = ATN, but use FEUrea <35% in patients on diuretics. Eosinophils in urine are sensitive but not specific for AIN; WBC casts support AIN; muddy brown granular casts = ATN. Hepatorenal syndrome is now treated with albumin + terlipressin (2022 FDA approval).

3Glomerular disease is high-yield: IgA nephropathy now has two targeted therapies (targeted-release budesonide — Nefecon/Tarpeyo — and sparsentan, dual endothelin/ARB). Membranous nephropathy: PLA2R antibody in 70-80% of primary cases, rituximab is first-line. Lupus nephritis class III/IV requires induction with IV cyclophosphamide or MMF plus steroids, and add-on belimumab or voclosporin improves outcomes. Anti-GBM = PLEX + cyclophosphamide + steroids. ANCA vasculitis — RAVE trial established rituximab as non-inferior to cyclo.

4Transplant: know 2014 allocation system (EPTS for recipient, KDPI for donor), standard induction (basiliximab for low-risk, ATG for high immunologic risk), maintenance triple therapy (tacrolimus + MMF + prednisone taper). Recognize BK virus nephropathy (reduce immunosuppression, no specific antiviral) vs CMV (ganciclovir/valganciclovir) vs PTLD (EBV-driven, reduce IS, rituximab). Banff grading: cellular rejection grade 1-3, antibody-mediated rejection requires C4d + DSA + morphology.

5Acid-base and electrolytes generate many questions: Winter's formula (expected PaCO2 = 1.5 x HCO3 + 8 ± 2), anion gap MUDPILES, osmolar gap + AG = methanol or ethylene glycol (fomepizole + HD). RTA type 1 (distal, urine pH >5.5, hypokalemia, kidney stones), type 2 (proximal, Fanconi, hypokalemia), type 4 (hyperkalemic, aldosterone deficiency). Hyperkalemia ladder: Ca gluconate (membrane), insulin+D50/albuterol (shift), patiromer or ZS-9 or dialysis (remove).

Frequently Asked Questions

Who is eligible for the ABIM Nephrology certification exam?

Candidates must hold current ABIM certification in Internal Medicine and must have completed a 24-month (2-year) ACGME-accredited fellowship in Nephrology. A valid, unrestricted US medical license and verification of clinical competence from the program director are also required.

How is the ABIM Nephrology exam structured?

It is a single-day, computer-based exam at Pearson VUE containing approximately 240 single-best-answer MCQs delivered in four modules of roughly two hours each, with an overall ~10-hour exam day including tutorial and breaks. It is offered annually in the fall.

What does the ABIM Nephrology exam cost in 2026?

The ABIM application plus exam fee for Nephrology is approximately $2,990 in 2026, with late fees applying after the regular deadline. Confirm the current ABIM fee schedule at abim.org because fees are updated annually.

What is the pass rate for the ABIM Nephrology boards?

ABIM-reported first-time pass rates for Nephrology have historically been in the 80-90% range, reflecting a fellowship-trained candidate pool. Pass rates for repeat takers are lower. See ABIM's annual pass-rate report for the most recent data.

What topics are highest-yield on the ABIM Nephrology boards?

CKD management (SGLT2i, finerenone, ACEi/ARB), CKD-MBD, glomerular diseases (IgA with sparsentan/Tarpeyo, membranous with PLA2R/rituximab, lupus nephritis class III/IV with belimumab/voclosporin), transplant immunosuppression and rejection (Banff grading, BK virus), dialysis (HD access, PD peritonitis, CRRT in ICU), and electrolyte/acid-base (hyponatremia, hyperkalemia, anion gap, RTAs, toxic alcohols).

What resources are recommended for Nephrology board prep?

The KDIGO guidelines (CKD 2024, AKI, CKD-MBD, glomerulonephritis, diabetes in CKD, transplant candidate evaluation) are essential. High-yield references include NephSAP (ASN self-assessment), Brenner & Rector's The Kidney, Comprehensive Clinical Nephrology (Feehally), and board-review courses (ASN Board Review, Mayo Nephrology Review). Practice questions with detailed rationales are critical.

How do I maintain ABIM Nephrology certification after passing?

ABIM offers continuous MOC via the Longitudinal Knowledge Assessment (LKA) — roughly 30 questions per quarter, open-book — or a traditional 10-year recertification exam. You must also keep your underlying Internal Medicine certification active and meet ABIM professional standing requirements.

Is ABIM Nephrology certification worth it career-wise?

Yes. Nearly all US dialysis units, kidney transplant programs, and hospital nephrology consult services require or strongly prefer board certification. Certified nephrologists typically earn a median salary of $280K-$350K, with significant additional income from dialysis medical directorships and partnerships in large dialysis organizations (DaVita, Fresenius).