- What This Certification Actually Is
- Who Issues It and Why That Matters
- The Two-Stage Structure: Written and Oral
- The Ten Content Areas and Where the Weight Sits
- Eligibility and Training Pathways
- The ABTS Written-Exam Credit Pathway
- Fees, Delivery and Scheduling Caveats
- Retakes, Active Status and Maintenance
- Sequencing Your Preparation Around the Blueprint
- Frequently Asked Questions
- This is the AOBS Primary Certification in Cardiothoracic Surgery, with AOA certification approval, built from a written stage and an oral stage.
- The written exam has 200 multiple-choice questions over four hours 30 minutes, with a scaled passing score of 500 on a 200-800 scale.
- Cardiac & Cardiac Surgery carries 49-53% of the written blueprint; Thoracic follows at 23-27%.
- Standard written and oral fees are $1,500 each, totaling $3,000 before any other costs.
What This Certification Actually Is
Primary Certification in Cardiothoracic Surgery is the board credential offered through the American Osteopathic Board of Surgery (AOBS), with certification approval from the American Osteopathic Association (AOA). It is the formal process by which a surgeon trained in cardiothoracic surgery demonstrates, through examination, the knowledge and clinical judgment expected of a board-certified practitioner in the specialty.
The credential is built around two examinations: a written exam that tests breadth of knowledge across ten content areas, and an oral exam that tests how you reason through clinical cases. Together they form the primary certification pathway. If you are still orienting yourself to the specialty itself, our explainers on what cardiothoracic surgery is and the broader cardiothoracic surgery certification landscape give useful background before you commit to a preparation plan.
This article is deliberately specific to the AOBS credential. Other certifying bodies run their own cardiothoracic examinations with different eligibility rules, formats, fees and scoring. None of those details apply here, and mixing them up is one of the most common mistakes candidates make when researching online.
Who Issues It and Why That Matters
The issuing body is the American Osteopathic Board of Surgery. That has practical consequences for candidates in three areas:
- Policies and notices: Deadlines, eligibility updates and exam announcements come from AOBS and AOA channels. The board's own pages and the application portal are the controlling sources.
- Remote testing rules: Remote delivery follows AOA instructions that name the MonitorEDU Secure Browser and PARADIGM testing.
- Maintenance framework: After certification, you remain in the AOA/AOBS maintenance structure known as OCC, with its own CME, assessment and quality-improvement components.
The Two-Stage Structure: Written and Oral
The written stage
The written exam consists of 200 multiple-choice questions delivered over four hours 30 minutes. The scaled passing score is 500 on a 200-800 scale. The fee is $1,500. Candidates can sit it remotely under the AOA's proctoring requirements, which means your testing environment and computer setup are part of the preparation, not an afterthought. For a closer look at how the scale works, see our guide to the cardiothoracic surgery passing score.
Because the blueprint is so heavily weighted toward one content area, the written exam rewards candidates who have genuine operative and perioperative depth in cardiac surgery rather than those with a thin, even spread of knowledge.
The oral stage
The oral exam also carries a $1,500 fee. It uses criterion-referenced clinical cases that assess diagnosis, investigations, differential diagnosis and management. In other words, examiners are looking at how you work through a patient problem: what you suspect, what you order, what else it could be, and what you do about it.
The sources do not specify an oral question count or a timer, and this article does not guess at either. The 2026 oral sitting was held September 30 in person in New Orleans. Candidates planning for future cycles should check the oral exam page and current notices for the location and format that apply to them.
| Feature | Written Exam | Oral Exam |
|---|---|---|
| Format | 200 multiple-choice questions | Criterion-referenced clinical cases |
| Time | Four hours 30 minutes | Not specified in verified sources |
| Fee | $1,500 | $1,500 |
| Scoring | Scaled passing score of 500 (200-800 scale) | Criterion-referenced |
| Delivery | Remote proctored (MonitorEDU Secure Browser, PARADIGM) | 2026 sitting held in person in New Orleans |
| Focus | Knowledge across ten content areas | Diagnosis, investigations, differential diagnosis, management |
The Ten Content Areas and Where the Weight Sits
The official Exam Content Outline for the written exam lists ten content areas, each with a published percentage range. The ranges below are the board's own and are not normalized or adjusted here. For a deeper walkthrough of each area, read our complete guide to all 10 cardiothoracic surgery content areas.
| Content Area | Published Range |
|---|---|
| Basic Science | 1-3% |
| Cardiac & Cardiac Surgery | 49-53% |
| Chest | 1-5% |
| Esophagus | 2-5% |
| Mediastinal (Mediastinum) | 1-4% |
| Osteopathic Manipulative Medicine | 1-3% |
| Other | 6-8% |
| Pulmonary | 2-6% |
| Thoracic | 23-27% |
| Trauma | 1-3% |
Reading the blueprint honestly
Two content areas, Cardiac & Cardiac Surgery and Thoracic, account for roughly three quarters of the exam at the midpoints of their ranges. The other eight areas share what remains. That asymmetry should drive how you allocate your time, but it should not make you ignore the smaller areas, since a handful of questions in each can still decide a borderline result.
Cardiac & Cardiac Surgery (49-53%)
This is the core of the exam. Expect questions that mirror what a practicing cardiac surgeon manages across the perioperative continuum.
- Operative indications, technique and decision-making across the range of adult cardiac surgical disease
- Perioperative and postoperative management, including complications and their recognition
- Interpretation of investigations that drive surgical decisions
- Judgment about when and how to intervene
Thoracic (23-27%)
The second-largest area covers the general thoracic side of the specialty. Candidates with a primarily cardiac practice often underestimate how much thoracic content they will face.
- Diagnostic workup and staging logic for thoracic disease
- Operative approaches and perioperative care
- Management of complications after thoracic procedures
Other (6-8%)
This category is larger than any of the smaller organ-system areas. Because it is a catch-all, review the official outline closely to see what falls under it rather than assuming it is trivial.
Osteopathic Manipulative Medicine (1-3%)
A small but distinctive slice that reflects the osteopathic certification context. It is easy to neglect and easy to pick up points on with brief, targeted review.
The smaller areas, which include Esophagus, Pulmonary, Chest, Mediastinal, Trauma and Basic Science, are best handled as efficient review blocks rather than extended study campaigns.
Eligibility and Training Pathways
Eligibility rests on approved training, active unrestricted licensure and required documentation. The specialty page retains the traditional description: four years of AOA-approved general surgery plus two years of cardiothoracic training, with program-director documentation. Current Board Policies additionally recognize qualifying DO/MD and ACGME routes.
Because the specialty page and the board policies describe the pathway slightly differently, do not rely on a single summary, including this one, to decide whether you qualify. Our cardiothoracic surgery requirements guide walks through the eligibility elements in more detail, and our overview of cardiothoracic surgery training covers the residency and fellowship side. The definitive answer for your situation comes from the AOBS Board Policies page and a conversation with the board office.
The ABTS Written-Exam Credit Pathway
An April 29, 2026 AOA announcement, published under the headline about a new subspecialty certification in neurocritical care and expanded AOBS eligibility, included a provision of particular interest to cardiothoracic candidates: AOBS recognizes a passed American Board of Thoracic Surgery (ABTS) written examination for the AOBS cardiothoracic oral-stage application.
It is important to read this precisely. It is credit within the selected AOBS pathway. It does not substitute an ABTS credential for AOBS certification, it does not import the ABTS syllabus into this exam, and it says nothing about ABTS pass rates being relevant here. A candidate who passed the ABTS written exam may be able to move to the AOBS oral stage on that basis, but the resulting credential is still the AOBS certification.
Candidates receiving written-exam credit should also not assume the same fee path as a standard candidate. The $3,000 total in this article reflects the standard written-plus-oral fees added together; confirm what applies to you with AOBS.
Fees, Delivery and Scheduling Caveats
The standard AOBS fees are $1,500 for the written exam and $1,500 for the oral exam, which adds up to $3,000. That figure excludes travel to an in-person oral sitting, study materials, review courses, licensure costs and any other expenses. For a fuller look at the money side, see our cardiothoracic surgery certification cost breakdown, and for the career-value question, our ROI analysis of the certification and salary guide.
Scheduling is where candidates get tripped up
Published scheduling information is not perfectly consistent:
- Specialty pages conflict on whether application lead time is five or six months, and they retain April scheduling language.
- The board homepage lists May 1-3, 2027 for the remote Spring Qualifying Examination.
- The 2026 oral exam sitting was September 30 in New Orleans.
The practical takeaway: treat the longer lead time as your planning assumption, and let current notices and the application portal resolve your individual deadline. Our exam dates and scheduling guide tracks how these windows are described.
Key Takeaway
When sources disagree on lead time, plan for the earlier deadline. Missing an application window costs far more than submitting a few weeks early, and the portal, not a blog post, is the final authority.
Retakes, Active Status and Maintenance
If you do not pass
The written-exam page requires reapplication after a failure. It describes a two-year retake window after the first or second failure. After a third written or oral failure, documented board-review study is required before another written attempt. If you want a realistic view of difficulty, read how hard the cardiothoracic surgery exam is. Note that no AOBS cardiothoracic-specific pass rate was verified, so our pass rate discussion explains what can and cannot be said responsibly.
After you pass
The specialty timeline describes primary active status for one year, subject to OCC (Osteopathic Continuous Certification). The maintenance components described by the board include:
- Licensure: Active licensure must be maintained.
- CME: 60 credits per three-year cycle for time-limited/OCC participants, confirmed by the current CME Requirements by Specialty Board document for 2025-2027, which supersedes the older CME-guide link.
- Longitudinal assessment: An annual assessment of 15 questions.
- Quality improvement: A QI/QA attestation every three years.
One wrinkle: the QI/QA page contains legacy wording about a 10-year cycle. That wording does not establish a new ten-year validity term, so do not plan around one.
Sequencing Your Preparation Around the Blueprint
The one planning principle that follows directly from the blueprint is to schedule by weight, not by comfort. A sensible arrangement for the written stage looks like this:
Cardiac & Cardiac Surgery
- Start here and return often, since it is roughly half the exam
- Build question practice into this block from the beginning
Thoracic, then Esophagus, Pulmonary and Mediastinal
- Treat Thoracic as a second major block
- Group the smaller organ-system areas together for efficient review
Other, OMM, Basic Science, Chest and Trauma
- Cover the small areas with targeted review
- Rehearse oral-style case reasoning aloud: diagnosis, investigations, differentials, management
For a full preparation framework, use our cardiothoracic surgery study guide and the one-page cheat sheet for last-stage review. Timed question practice matters here because 200 questions in four hours 30 minutes is a sustained effort, and our cardiothoracic surgery practice tests are built to help you rehearse that pacing against the real blueprint. Employers and career paths are covered separately in our overview of cardiothoracic surgery jobs.
Frequently Asked Questions
It is the board certification offered through the American Osteopathic Board of Surgery (AOBS), with AOA certification approval. It consists of a written stage and an oral stage and is the primary credential for cardiothoracic surgeons in this pathway.
The written exam has 200 multiple-choice questions and runs four hours 30 minutes. The scaled passing score is 500 on a 200-800 scale, and the fee is $1,500.
Cardiac & Cardiac Surgery is the largest at 49-53%, followed by Thoracic at 23-27%. The remaining eight areas, including Other at 6-8%, split the rest of the blueprint.
An April 29, 2026 AOA announcement says AOBS recognizes a passed ABTS written examination for the AOBS cardiothoracic oral-stage application. It is credit within the AOBS pathway, not a substitute for AOBS certification, and fee details should be confirmed with the board.
The standard written ($1,500) and oral ($1,500) fees total $3,000. That excludes travel, study materials, licensure and other costs, and it may not apply identically to candidates receiving written-exam credit.
You enter primary active status, described as one year and subject to OCC. Maintenance includes active licensure, 60 CME credits per three-year cycle, an annual 15-question longitudinal assessment and a QI/QA attestation every three years.