Nephrology Cheat Sheet 2026: One-Page Review of Must-Know Facts

Quick Facts Snapshot

This cheat sheet compresses the essential mechanics of Certification in Nephrology under the American Osteopathic Board of Internal Medicine (AOBIM) into a single reference page. It is built strictly around the AOBIM initial adult nephrology subspecialty Written Exam - not around any other credential that shares similar naming. Bookmark this page and use it as a final review the week before your test date, or as an orientation document when you first begin planning.

For a full breakdown of how these figures fit into total cost of certification, see the Nephrology Certification Cost 2026 pricing breakdown. If you want the underlying eligibility rules explained in detail, review Nephrology Requirements 2026.

Registration & Fee Mechanics

Application timing is unforgiving, so treat these dates as fixed anchors in your planning calendar. For the 2026 cycle, nephrology applications opened February 16 and closed July 16. The standard $800 fee applies through June 16; after that date, a $240 late fee is added on top of the standard fee, and July 16 is the hard final cutoff for applications. There is no indication of a separate late window beyond that date, so candidates who miss July 16 should expect to wait for the next cycle.

Eligibility itself has several moving parts: primary AOA/AOBIM internal medicine certification, two years of ACGME-accredited or AOA-recognized nephrology fellowship training, active medical licensure, program-director verification of clinical competence and training completion, and compliance with AOA ethical requirements. General board policy also allows qualifying COCA-accredited osteopathic or LCME-accredited medical graduates to sit for subspecialty certification, provided the applicable accredited training requirements are still met. Board eligibility itself ends December 31 of the sixth year following training completion, so candidates who delay taking the exam risk losing eligibility entirely. A detailed explanation of each of these criteria - including how program-director attestations work - is covered in the Nephrology Requirements guide.

Domain-by-Domain Cheat Sheet

The official Written Exam outline organizes content into 23 topic areas, each with a published percentage range rather than a fixed weight. Ranges give you flexibility in item-writing from year to year, but they also tell you where to invest study hours. Below is the full list condensed for quick reference; for an expanded walkthrough of each area with clinical vignette guidance, see the Nephrology Exam Domains 2026 complete guide.

The remaining 20 domains each carry ranges between 1% and 9%, covering everything from fluid and electrolyte physiology to familial kidney disorders. A compact list:

• Fluid, acid-base, electrolyte physiology/renal function testing (2-6%)
• Mineral metabolism/disorders - PO4, Ca, Mg (2-6%)
• Hypo/Hypernatremia (2-6%)
• Hypo/Hyperkalemia (1-5%)
• Pregnancy and the kidney (1-3%)
• Overdose/Toxic nephropathy/Intoxication (1-5%)
• Primary glomerular disease (5-9%)
• Secondary glomerular disease (4-8%)
• Diabetic nephropathy (2-6%)
• Hypertension (3-7%)
• Chronic kidney disease (3-7%)
• Peritoneal dialysis (3-7%)
• Renal transplantation (3-7%)
• Vasculitis/Vascular disorders of kidney (1-5%)
• Tubulointerstitial disease (1-5%)
• Urolithiasis (1-3%)
• Obstructive uropathy (1-3%)
• Urinary tract infections/Pyelonephritis (1-4%)
• Cystic disease/UT Anomalies (2-6%)
• Familial disorders of kidney (1-5%)

The Three Highest-Yield Domains

If your review time is limited, prioritize acid-base/RTA, AKI, and hemodialysis first, since together they can account for roughly a fifth to a third of the entire exam depending on how the ranges land in a given administration. Primary glomerular disease (5-9%) and secondary glomerular disease (4-8%) round out the next tier, followed by chronic kidney disease, peritoneal dialysis, hypertension, and renal transplantation, each capped at 7%.

Candidates preparing for these three domains should also review how question stems are typically constructed - long clinical vignettes with labs, imaging references, and medication histories embedded, requiring you to synthesize rather than recall isolated facts. This question style is discussed further in the How Hard Is the Nephrology Exam difficulty guide.

Scoring & Passing Threshold

Passing the Written Exam requires a scaled score of at least 500 on a 200-800 scale - this is not a fixed raw percentage of correct answers, and the scaling accounts for item difficulty across different exam forms. Because the scale is not a simple percent-correct conversion, candidates should avoid fixating on "how many questions can I miss" arithmetic and instead focus on consistent performance across all 23 domains. A full explanation of how the scaled score works and what it implies for your study strategy is available in Nephrology Passing Score 2026: Exactly What You Need to Pass.

If you're deciding whether the investment of time and the $800 fee (plus possible $240 late fee) is worthwhile relative to your career plans, the Is the Nephrology Certification Worth It ROI analysis walks through that decision in more depth, and Nephrology Jobs covers where certified nephrologists typically find employment after passing.

OCC and Recertification Facts

Passing the initial Written Exam is not the end of the certification lifecycle. Certification carries a ten-year term subject to successful Osteopathic Continuous Certification (OCC). For the 2025-2027 cycle, time-limited diplomates must complete 60 CME credits over three years, including at least 15 Category 1 and/or Category 1-A credits, maintain active licensure, attest to one quality-improvement activity per three-year cycle, and pass the required subspecialty OCC cognitive examination.

It's worth being explicit here: AOBIM initial nephrology certification, ABIM nephrology certification, and nephrology OCC are three distinct processes with different governing bodies and different requirements. Do not substitute ABIM blueprints, timelines, or longitudinal-assessment models when planning your AOBIM OCC cycle - the credentials are not interchangeable, and mixing up requirements between AOBIM vs ABIM nephrology pathways is one of the most common candidate mistakes.

One-Week Review Schedule

In the final week before your exam date, structure review sessions around domain weight rather than alphabetical order or textbook chapter sequence. A short, focused schedule like the one below works well when layered on top of a longer-term study plan; for a full multi-month plan, see the Nephrology Study Guide 2026: How to Pass on Your First Attempt.

Running a full-length timed set matters because the real exam is 300 questions across seven hours - pacing fatigue is a real factor, not just content mastery. You can build that stamina using full-length practice tests modeled on the official exam format well before your scheduled test date.

Putting the Cheat Sheet to Work

Use this page as a checklist, not a replacement for deep content review. Confirm your eligibility status against the requirements checklist, verify your target testing window against the Nephrology Exam Dates 2026 guide, and calibrate your expectations about difficulty using the Nephrology Pass Rate data. Then return to the domain list above weekly to track which areas still need reinforcement.

For candidates still early in fellowship or considering whether to pursue this pathway at all, background context is available in What Is Nephrology Certification? and Nephrology Training. Once you're ready to test your recall against exam-style items, start a practice session to benchmark your current readiness.

Frequently Asked Questions