- What This Credential Actually Is
- Who Qualifies to Sit
- The Written Exam: Format, Fee and Delivery
- Where the Points Live: The Ten Content Areas
- The Oral Stage: Clinical Cases, Not Recall
- The ABTS Written-Exam Credit Rule
- Fees, Deadlines and Source Caveats
- Sequencing Your Preparation Around the Blueprint
- If an Attempt Does Not Go Your Way
- Keeping the Certificate Current
- Frequently Asked Questions
- This is the AOBS Primary Certification in Cardiothoracic Surgery, with written and oral stages, each carrying a $1,500 fee.
- The written exam has 200 multiple-choice questions over four hours thirty minutes; the passing scaled score is 500 on a 200-800 scale.
- Cardiac & Cardiac Surgery (49-53%) and Thoracic (23-27%) together make up roughly three-quarters of the written blueprint.
- A passed ABTS written examination is credited toward the AOBS cardiothoracic oral-stage application, but it does not substitute for the credential.
What This Credential Actually Is
The certification discussed here is Primary Certification in Cardiothoracic Surgery, issued by the American Osteopathic Board of Surgery (AOBS) with AOA certification approval. It is a two-stage process: a written examination followed by an oral examination. It is a board credential for surgeons, not a technologist or allied-health certificate, and it should not be confused with other credentials that happen to be abbreviated similarly. If you need background on the field itself before diving into the exam mechanics, see our explainers on what cardiothoracic surgery is and what cardiothoracic surgery certification means.
Everything below is drawn from the AOBS written-exam content outline, the oral-exam page, the AOBS board policies and the AOA's published notices. Where those sources disagree or are under revision, this article says so rather than papering over the gap.
Who Qualifies to Sit
Eligibility rests on three pillars: approved training, an active unrestricted license, and the documentation the board requires. The cardiothoracic specialty page describes the traditional osteopathic route as four years of AOA-approved general surgery plus two years of cardiothoracic training, supported by program-director documentation. Current AOBS Board Policies also recognize qualifying DO/MD and ACGME-accredited routes, so your training history may not look like the legacy description at all.
The Written Exam: Format, Fee and Delivery
The written stage is a straightforward high-stakes recall-and-judgment test, and the numbers are fixed:
| Element | Detail |
|---|---|
| Question count | 200 multiple-choice questions |
| Time allowed | Four hours thirty minutes |
| Fee | $1,500 |
| Passing standard | Scaled score of 500 on a 200-800 scale |
| Remote delivery | MonitorEDU Secure Browser and PARADIGM testing, per AOA instructions |
Doing the arithmetic, 270 minutes across 200 items gives you about 81 seconds per question. That is workable for a clean stem-and-options item, but it leaves little room for rereading long operative or critical-care vignettes. Practice at pace early; our passing score explainer covers how scaled scoring works and why the number you see is not a raw percentage.
Remote Proctoring Mechanics
When the exam is offered remotely, candidates follow the AOA's remote-proctored exam instructions, which name the MonitorEDU Secure Browser and the PARADIGM testing platform. Run the technical check well before exam day, and read the AOA page directly, since software requirements change more often than exam content does.
Where the Points Live: The Ten Content Areas
The AOBS Exam Content Outline publishes a percentage range for each of ten areas. These ranges are reproduced as published, without normalization, so they will not sum to a clean 100%. Use them as a weighting guide rather than an exact item count. For the full per-domain treatment, see our complete guide to all 10 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% |
Cardiac & Cardiac Surgery (49-53%)
This is the exam. Roughly half the questions come from here, so a weakness in this area cannot be rescued by strength elsewhere.
- Operative indications and technique across valvular, coronary and aortic disease
- Perioperative and postoperative cardiac management, including cardiopulmonary bypass considerations
- Complications, their recognition and their management
- Congenital and adult cardiac disease as they appear in the outline
Thoracic (23-27%)
The second-largest block, and the one where surgeons trained primarily in cardiac work most often discover gaps.
- Lung and pleural disease requiring surgical decision-making
- Resection strategy, staging logic and perioperative risk assessment
- Management of thoracic complications
The Small but Not Negligible Areas
Esophagus (2-5%), Pulmonary (2-6%), Chest (1-5%), Mediastinal (1-4%), Trauma (1-3%), Basic Science (1-3%) and Osteopathic Manipulative Medicine (1-3%) each look minor alone. Combined, they are a meaningful slice, and "Other" (6-8%) is larger than most of them individually. Do not skip OMM simply because it feels peripheral to a surgical specialty; it is a published content area on an osteopathic board examination.
The Oral Stage: Clinical Cases, Not Recall
The oral stage carries its own $1,500 fee and is criterion-referenced. Candidates work through clinical cases that assess diagnosis, investigations, differential diagnosis and management. The published sources do not give an oral question count or a per-case timer, so any figure you see quoted elsewhere is not verified from the board. The 2026 oral sitting was held September 30 in person in New Orleans.
The skill being tested differs from the written exam. Written items let you recognize a correct answer among options; oral cases require you to construct a workup and defend a plan aloud. Practice by narrating your reasoning in sequence: what you would order, what each result changes, what the differential still contains, and what you would do next. Our difficulty guide discusses why candidates often find the oral stage more demanding than the written despite its smaller footprint on paper.
The ABTS Written-Exam Credit Rule
An April 29, 2026 AOA announcement (published alongside news of a new neurocritical care subspecialty certification) stated that AOBS expanded certification eligibility and now recognizes a passed ABTS written examination for the AOBS cardiothoracic oral-stage application.
Fees, Deadlines and Source Caveats
On the standard path, the published fees are $1,500 for the written stage and $1,500 for the oral stage, which adds up to $3,000 before any other costs such as travel, lodging, review materials or time away from practice. See the full pricing breakdown for how to budget the rest.
Deadlines are where the board's own pages disagree, and honesty here matters more than a tidy answer:
- Different specialty pages cite five months versus six months of application lead time.
- Some pages retain April scheduling language, while the AOBS homepage lists May 1-3, 2027 for the remote Spring Qualifying Examination.
- The Protocol for Certification is under revision, so there is no current handbook to arbitrate.
The practical rule: assume the longer lead time, check the current notices page, and let the application portal be the final word on your individual deadline. Our exam dates guide tracks the scheduling windows as they are confirmed.
Sequencing Your Preparation Around the Blueprint
Generic study advice is plentiful; what matters here is allocation. Because Cardiac & Cardiac Surgery plus Thoracic account for roughly three-quarters of the blueprint, your calendar should look lopsided on purpose. For a fuller plan, see the study guide; the outline below shows how the weighting translates into weeks.
Cardiac & Cardiac Surgery, first pass
- Work valvular, coronary and aortic topics in operative-decision order
- Log every missed question by sub-topic, not just by score
Thoracic, with Pulmonary and Chest alongside
- Pair lung and pleural surgery with the pulmonary physiology that drives candidacy decisions
- Add Mediastinal and Esophagus here, since they share anatomy and workup logic
The small areas and "Other"
- Basic Science, Trauma and Osteopathic Manipulative Medicine in short, targeted sessions
- Review the "Other" bucket, which is larger than any single minor area
Timed mixed sets
- Practice at roughly 81 seconds per item under the real 200-question, 270-minute structure
- Return to the cardiac bucket for a second pass on your logged weak spots
If your clinical practice is cardiac-heavy, shift the thoracic weeks earlier rather than later; the topics you see daily in the OR are the ones you will overestimate. Timed question banks at our practice test site are useful for the final phase, and the one-page cheat sheet works well as a last-week reference.
Key Takeaway
Allocate preparation time in proportion to the published ranges. If half your calendar is not devoted to Cardiac & Cardiac Surgery and roughly a quarter to Thoracic, your plan does not match the exam.
If an Attempt Does Not Go Your Way
The written-exam page spells out the consequences of failure:
- After a failed attempt, you must reapply rather than simply rebook.
- A two-year retake window applies after the first or second failure.
- After a third written/oral failure, you must document board-review study before another written attempt.
No AOBS cardiothoracic-specific pass rate has been verified, so be skeptical of any pass-rate figure presented as fact. Our pass rate analysis explains what is and is not known.
Keeping the Certificate Current
Certification is not a one-time event. The specialty timeline describes primary active status for one year, subject to participation in Osteopathic Continuous Certification (OCC). The maintenance components are:
- Active licensure maintained throughout
- 60 CME credits per three-year cycle, confirmed by the current CME Requirements by Specialty Board document for 2025-2027, which supersedes the older CME-guide link
- Annual longitudinal assessment consisting of 15 questions
- QI/QA attestation every three years
One wrinkle: the QI/QA page contains legacy 10-year-cycle wording. That language does not establish a new ten-year validity term, so do not plan around one. For the career-value side, weigh these obligations against the benefits in our ROI analysis, and see cardiothoracic surgery jobs and the salary guide for what employers and compensation look like, noting that this site does not publish unverified earnings figures here.
Frequently Asked Questions
The American Osteopathic Board of Surgery (AOBS), with AOA certification approval. It is the Primary Certification in Cardiothoracic Surgery and includes both written and oral stages.
The written exam has 200 multiple-choice questions and allows four hours thirty minutes. The passing score is a scaled 500 on a 200-800 scale.
Cardiac & Cardiac Surgery is the largest at 49-53%, followed by Thoracic at 23-27%. The remaining eight areas, including Other at 6-8%, share the rest of the blueprint.
Per the April 29, 2026 AOA announcement, AOBS recognizes a passed ABTS written examination for the cardiothoracic oral-stage application. This is credit within the AOBS pathway, not a replacement for an ABTS credential, and fee handling for such candidates should be confirmed with the board.
Active licensure, 60 CME credits per three-year cycle, a 15-question annual longitudinal assessment and a QI/QA attestation every three years. Legacy 10-year wording on one page does not create a ten-year validity term.
For a broader overview of the credential, start with our main Cardiothoracic Surgery Certification page, and when you are ready to test yourself against exam-style questions, head to the practice test site.