How Hard Is the CHS Exam? Complete Difficulty Guide 2026

What Actually Makes the CHS Exam Difficult

The Certification in Congenital Cardiac Surgery (CHS), administered by the American Board of Thoracic Surgery (ABTS) as its Congenital Heart Surgery subspecialty credential, is not difficult in the way a broad-coverage licensing exam is difficult. It's difficult because it sits at the intersection of an already narrow specialty - congenital cardiac surgery - and a testing format that leaves little room for partial knowledge. Candidates arrive as already-certified thoracic surgeons who have completed additional congenital training, so the exam isn't testing whether you can be a surgeon. It's testing whether you can reliably reconstruct the anatomic, physiologic, and operative reasoning behind dozens of rare and overlapping congenital lesions under time pressure, and then defend that reasoning verbally in front of examiners.

That combination - dense subspecialty content, a written-then-oral gate, and small candidate pools with less normed data than larger boards - is what candidates usually mean when they ask how hard CHS really is. For a full breakdown of exactly what's being tested, see the CHS Exam Domains 2026 guide, which walks through all 11 content areas in detail.

The Two-Part Structure: Written Then Oral

CHS certification is built as a sequential gate, not a single test day. Part I is a written multiple-choice examination delivered at Pearson Professional Testing Centers. You must pass Part I before you're permitted to sit Part II, the oral examination, which is conducted in person. For the 2026-2027 cycle, the written window is December 7-11, 2026, with the corresponding oral examination scheduled for June 4-5, 2027 in Dallas. That gap of roughly six months between written and oral is itself a difficulty factor: candidates have to sustain preparation momentum across two very different assessment formats without a fixed short runway between them.

This structure means "how hard is CHS" really breaks into two separate questions: how hard is the written exam, and how hard is the oral exam. They test overlapping content but different skills - recognition and recall under a three-option MCQ format versus live case reasoning and verbal defense of operative decisions in front of examiners. For a date-by-date breakdown of the current cycle, see CHS Exam Dates 2026.

The 11 Content Domains That Define Difficulty

The unweighted content categories that structure CHS preparation cover the full landscape of congenital cardiac disease, from straightforward septal defects to complex single-ventricle physiology. Difficulty is not evenly distributed across these domains - some are conceptually dense because they combine multiple anatomic variants, staged surgical strategies, and overlapping nomenclature.

• Domain 1: Septal Defects
• Domain 2: Anomalies of Venous Connection
• Domain 3: Anomalies of the Aorta, Aortic Arch, and Coronary Arteries
• Domain 4: Anomalies of the Tricuspid and Mitral Valves
• Domain 5: Anomalies of the Aortic Valve and Left Ventricular Outflow Tract
• Domain 6: Anomalies of the Pulmonary Valve and Right Ventricular Outflow Tract
• Domain 7: Conotruncal Anomalies
• Domain 8: Anomalies of Atrioventricular Connection, Univentricular Heart, and Atrial/Visceral Situs
• Domain 9: Diseases of the Myocardium
• Domain 10: Pre-, Intra-, and Post-Operative Evaluation and Management of Congenital Cardiac Disease
• Domain 11: Acquired Cardiovascular Diseases in Infants and Children

Because these categories are unweighted, candidates can't assume any domain is "worth less" study time. The CHS Study Guide 2026 goes further into sequencing all 11 domains into a workable preparation plan.

What the Pass Rate Data Actually Shows

ABTS reported 7 passes among 8 written examinees and 4 passes among 4 oral examinees in 2025. Those numbers look reassuring at first glance, but the cohort sizes are extremely small, and ABTS itself frames them as figures to interpret cautiously. A single-digit candidate pool means one or two outcomes shift the "rate" dramatically - this is not a statistically stable pass rate in the way a large licensing exam's numbers are. Candidates should not read these figures as a guarantee of an easy pass, nor as evidence the exam is harsher than it looks. For a fuller discussion of what these numbers do and don't tell you, see CHS Pass Rate 2026: What the Data Shows.

Three-Option MCQs and What They Change

Beginning in 2025, CHS written multiple-choice questions use three answer options rather than the four or five options common on many exams. This is a meaningful shift in test-taking mechanics. Fewer options generally raise the baseline probability of a correct guess, but they also compress the space for plausible distractors - meaning the wrong answers are often closer to correct, forcing finer discrimination between similar-sounding management choices or anatomic variants. In practice, this rewards candidates who understand the underlying reasoning well enough to eliminate a subtly wrong answer, rather than those who memorize surface-level facts. Exact scoring thresholds and how they interact with this format are covered in CHS Passing Score 2026.

Eligibility Hurdles Before You Even Sit the Exam

A significant part of CHS difficulty happens before test day. Initial eligibility requires current primary ABTS certification, unrestricted medical licensure, qualifying thoracic and congenital cardiac surgery training, verified operative experience, and formal program endorsement. For fellows starting on or after July 1, 2023, the training requirement is specific: two consecutive years in a single ACGME-accredited program and at least 150 major congenital cases, including at least 50 in the first year alone. That case volume requirement means candidates can't simply "study harder" to compensate for a thin operative record - the eligibility bar is structural, not something a review course can fix. Full detail on every prerequisite lives in CHS Requirements 2026.

Cost as a Difficulty Multiplier

CHS's difficulty isn't purely cognitive - it's financial. Initial fees total $4,900: a $650 application fee, $1,750 for the written examination, and $2,500 for the oral examination, all before travel and preparation costs, including the trip to Dallas for the in-person oral. That total puts pressure on candidates to prepare thoroughly enough to pass each stage on the first attempt, since re-testing means paying the associated fee again. A detailed cost breakdown, including how the fee structure compares across the pathway, is available in CHS Certification Cost 2026.

Building a Study Timeline Around the Hardest Domains

Generic study techniques - spaced repetition, focused review blocks, active recall - only matter here if they're mapped onto the specific structure of CHS. Given the written exam falls in December 2026 and the oral follows in June 2027, a sensible approach is to front-load the densest, most conceptually tangled domains early, then use the written-to-oral gap to convert that same content into verbal case-presentation fluency.

Running timed drills against a realistic three-option format throughout this window is one of the more direct ways to rehearse the actual test mechanics - the practice test platform is built around that exact CHS-specific structure rather than generic surgical trivia.

Written vs. Oral: A Side-by-Side Difficulty Comparison

Notice that the oral exam carries both the higher fee and the higher stakes conversational demand - it's the stage where knowledge has to be produced live, not just recognized on a screen. Candidates who treat Part I purely as a memorization exercise sometimes struggle to convert that same knowledge into the spoken, case-driven format Part II requires. Understanding this distinction early is one of the clearer ways to gauge how hard CHS will feel for your particular strengths - for more on what the credential actually represents day to day, see What Is CHS Certification? and CHS Certification.

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