- Why 21 Domains Define the Pulmonary Disease Exam
- How AOBIM Weights the 21 Content Areas
- The Highest-Yield Domains to Prioritize
- Full Breakdown of All 21 Domains
- Exam Format, Fees & Registration Logistics
- Mapping the 21 Domains to a Study Timeline
- Who Hires Pulmonary Disease-Certified Physicians
- Frequently Asked Questions
- AOBIM's blueprint lists exactly 21 content areas, each published as a percentage range, not a fixed weight.
- Interstitial lung disease and Pneumonia/pulmonary infections tie as the largest domains at 10-14% each.
- Interpretation of PFTs (7-11%) and Tuberculosis (6-10%) round out the four heaviest-tested areas.
- The initial exam is 300 multiple-choice questions over 7 hours, with a passing score of 500 on the 200-800 scale.
Why 21 Domains Define the Pulmonary Disease Exam
Unlike exams built around three or four broad categories, the AOBIM Subspecialty Certification in Pulmonary Disease exam is organized into 21 distinct content areas. That granularity matters: it tells you precisely how the examination committee carves up the field of pulmonary medicine, and it gives you a map for allocating study hours instead of guessing. Each of the 21 areas is paired with a published percentage range - not a single fixed weight - which means AOBIM reserves flexibility in exactly how many items appear from each domain on any given form.
This guide walks through every one of the 21 domains using the exact names and ranges transcribed from AOBIM's current online blueprint, explains how the ranges work (and don't work), and shows how to sequence your preparation around the domains that carry the most point value. If you haven't yet reviewed the broader mechanics of the exam, pair this guide with our Pulmonary Disease Study Guide 2026 for a first-attempt study plan, and check Pulmonary Disease Requirements 2026 to confirm you're eligible to sit before you build a domain-by-domain schedule.
How AOBIM Weights the 21 Content Areas
AOBIM publishes percentage ranges for each domain rather than fixed weights, and that distinction should shape how you interpret this blueprint. A range like 10-14% does not mean exactly 12% of questions, and the 21 ranges are not designed to sum neatly to 100% when you add midpoints. Don't force the numbers into a precise question count per domain - AOBIM does not publish exact item counts by content area, and any claim that does so is not coming from the official source.
What the ranges do tell you is relative emphasis. A domain sitting at 1-3% (like Sarcoidosis or Bronchiectasis/cystic fibrosis) will never dominate your score the way a 10-14% domain can. Scoring itself works on the AOA's 200-800 scaled system with a passing score of 500 - results are based on total correctly answered items across the whole 300-question exam, not an average of per-domain percentages. For a deeper dive into exactly what that scaled score means, see Pulmonary Disease Passing Score 2026.
Key Takeaway
Use the published ranges to rank domains by relative importance, not to calculate an exact number of questions. Spend study time proportional to the range, and never assume a domain's score is isolated from your overall scaled result.
The Highest-Yield Domains to Prioritize
Four domains carry the widest and highest percentage ranges on the blueprint, which makes them the natural backbone of any study plan.
Domain 6: Interstitial Lung Disease (10-14%)
Tied for the largest single domain on the exam. Candidates need command of the full spectrum of diffuse parenchymal lung disease - classification schemes, HRCT pattern recognition, and the clinical workup that distinguishes idiopathic pulmonary fibrosis from other ILD subtypes.
- Radiographic pattern recognition (UIP vs. NSIP vs. organizing pneumonia patterns)
- Diagnostic algorithms, including when biopsy is indicated
- Disease-specific management differences across ILD subtypes
Domain 7: Pneumonia/Pulmonary Infections (10-14%)
The other domain tied for largest share of the exam. Expect questions spanning community-acquired, hospital-acquired, and opportunistic infections, plus the immunocompromised host.
- Pathogen-specific presentations and empiric therapy selection
- Severity scoring and site-of-care decisions
- Complications requiring escalation of care
Domain 19: Interpretation PFTs (7-11%)
Pulmonary function testing interpretation is tested heavily and independently from the disease-specific domains, meaning you need fluency reading flow-volume loops and spirometry patterns in isolation, not just as an afterthought within disease questions.
- Obstructive vs. restrictive pattern recognition
- DLCO interpretation in mixed-pattern disease
- Bronchodilator response and reversibility criteria
Domain 8: Tuberculosis (6-10%)
A single-disease domain earning a surprisingly wide range, reflecting the breadth of TB testing, latent vs. active disease management, and multidrug-resistant treatment regimens candidates are expected to know cold.
- Diagnostic testing - IGRA vs. TST indications
- Treatment regimens and duration for latent vs. active TB
- Drug-resistant TB management principles
Together, these four domains alone can account for a sizable share of the 300-item exam. Build your early study weeks around them before moving to the narrower domains, a sequencing approach covered in more detail in our Pulmonary Disease Cheat Sheet 2026.
Full Breakdown of All 21 Domains
Below is the complete list as transcribed from AOBIM's current online table. Use the ranges to prioritize, not to calculate exact question counts.
| # | Domain | Percentage Range |
|---|---|---|
| 1 | Respiratory structure and function | 2-6% |
| 2 | Asthma | 3-7% |
| 3 | Chronic bronchitis and emphysema | 4-8% |
| 4 | Sleep disorders | 3-7% |
| 5 | Bronchiectasis/cystic fibrosis | 1-3% |
| 6 | Interstitial lung disease | 10-14% |
| 7 | Pneumonia/pulmonary infections | 10-14% |
| 8 | Tuberculosis | 6-10% |
| 9 | Benign/malignant neoplasms | 2-6% |
| 10 | Occupational disorders | 1-5% |
| 11 | Sarcoidosis | 1-3% |
| 12 | Lung abscess | 1-5% |
| 13 | Physical, chemical, and aspiration injuries | 2-6% |
| 14 | Disorders of diaphragm, chest wall, pleura, and mediastinum | 1-4% |
| 15 | Disorders of ventilatory control | 2-6% |
| 16 | Pulmonary hypertension/vascular disorders | 1-5% |
| 17 | PE/DVT | 1-5% |
| 18 | Interpretation imaging studies/pathologic specimens | 1-5% |
| 19 | Interpretation PFTs | 7-11% |
| 20 | ARDS/respiratory failure | 4-8% |
| 21 | ICU management/ventilatory care | 1-5% |
A few of these mid-tier domains deserve a closer look, since they're easy to under-study relative to their actual point value.
Domain 20: ARDS/Respiratory Failure (4-8%)
Overlaps heavily with critical care content - ventilator management principles, Berlin criteria for ARDS classification, and rescue strategies for refractory hypoxemia.
- ARDS severity classification and oxygenation targets
- Lung-protective ventilation strategies
- Indications for prone positioning and rescue therapies
Domain 3: Chronic Bronchitis and Emphysema (4-8%)
COPD staging, exacerbation management, and the pharmacologic stepwise approach remain core clinical knowledge tested across multiple question formats.
- GOLD-style staging and symptom burden assessment
- Exacerbation triggers and escalation of therapy
- Long-term oxygen and surgical/endobronchial options
Exam Format, Fees & Registration Logistics
The Pulmonary Disease exam is a written, computer-based multiple-choice examination covering basic science and clinical knowledge and interpretation across the 21 domains above. It consists of 300 multiple-choice questions administered over a 7-hour testing session, as described by AOBIM. The page does not separately itemize active testing time, tutorials, or break allowances, so plan your pacing around the full 7-hour window rather than assuming a specific split.
Passing requires a scaled score of 500 or higher on the AOA's 200-800 scale. This is not equivalent to 62.5% of items correct - the score is scaled, and your overall result is based on total correctly answered questions across the exam rather than an average of domain-level performance. For registration logistics, including the currently posted initial-exam fee of $800 and a $240 late fee, see our dedicated Pulmonary Disease Certification Cost 2026 breakdown - note that the pulmonary exam page still displays a March-July 2025 application window, so these are posted figures to verify, not guaranteed 2026 checkout prices.
Eligibility requires AOA/AOBIM primary certification in internal medicine plus two years of an ACGME-accredited or AOA-recognized pulmonary (or combined pulmonary/critical-care) fellowship completed by August 15 of the examination year, along with an active license, completed application and fees, adherence to AOA ethics standards, and a program-director report confirming clinical competence. Full details live in our Pulmonary Disease Requirements 2026 guide. For testing-window specifics and deadlines, check Pulmonary Disease Exam Dates 2026 before you finalize a study calendar.
Key Takeaway
Because remote-exam guidance from AOA requires a private room, a compatible computer with administrator access, a mobile camera device, and a secure browser, confirm your testing setup weeks in advance rather than the night before your scheduled date.
Mapping the 21 Domains to a Study Timeline
Rather than studying the 21 domains in blueprint order, sequence them by weight so your earliest, highest-energy study weeks cover the content that carries the most points. A domain-weighted timeline also makes later review passes faster, since you'll already have deep familiarity with the heaviest topics by the time you reach full-length practice on our practice test platform.
Largest Domains First
- Interstitial lung disease (10-14%)
- Pneumonia/pulmonary infections (10-14%)
PFTs and Tuberculosis
- Interpretation PFTs (7-11%) - drill flow-volume loops daily
- Tuberculosis (6-10%) - latent vs. active regimens
Mid-Tier Clinical Domains
- Chronic bronchitis and emphysema, Asthma, ARDS/respiratory failure
- Sleep disorders and ventilatory control disorders
Narrow-Range Domains and ICU Topics
- PE/DVT, pulmonary hypertension, occupational disorders, neoplasms
- Sarcoidosis, bronchiectasis/CF, lung abscess, chest wall/pleura/mediastinum disorders
- ICU management/ventilatory care, imaging/pathologic specimen interpretation
Full-Length Review
- Timed practice blocks mirroring the 7-hour format
- Weak-domain targeted review based on practice results
This sequencing pairs well with a lighter application of traditional study techniques - spaced repetition flashcards work especially well for the Tuberculosis regimen details and PFT pattern recognition, since both reward frequent, short review cycles rather than long single sessions. For a complete walkthrough of pacing, resource selection, and review cadence, see the Pulmonary Disease Study Guide 2026. If you're still assessing overall difficulty before committing to a timeline, read How Hard Is the Pulmonary Disease Exam? and Pulmonary Disease Pass Rate 2026 for context on what you're preparing against.
Who Hires Pulmonary Disease-Certified Physicians
Subspecialty Certification in Pulmonary Disease signals to hospitals, multi-specialty groups, and academic pulmonary/critical-care divisions that a physician has met AOBIM's training and examination standard beyond internal medicine primary certification. Because the certification pathway requires a completed pulmonary (or combined pulmonary/critical-care) fellowship on top of internal medicine certification, it's typically a credential pursued by physicians already committed to pulmonology as a long-term specialty rather than a general internist adding a credential opportunistically.
If you're weighing whether to pursue certification at all, our Is the Pulmonary Disease Certification Worth It? analysis and Pulmonary Disease Salary Guide 2026 cover the career-side considerations in depth. For a broader look at the field itself and how this credential fits into it, see What Is Pulmonary Disease Certification? and browse current openings through Pulmonary Disease Jobs.
Once you've reviewed all 21 domains conceptually, the next step is applying that structure to timed practice questions that mirror the real exam's format and pacing - a resource you can start using right away on the main practice test platform.
Frequently Asked Questions
AOBIM's current blueprint lists 21 official content areas, each assigned a percentage range rather than a fixed weight, covering everything from respiratory structure and function to ICU management and ventilatory care.
Interstitial lung disease and Pneumonia/pulmonary infections are jointly the largest at 10-14% each, followed by Interpretation PFTs at 7-11% and Tuberculosis at 6-10%.
No. AOBIM publishes ranges, not fixed weights, so the ranges are not designed to sum to exactly 100% when combined, and individual question counts per domain are not published.
The initial certification exam contains 300 multiple-choice questions administered over 7 hours. This question count applies to the initial exam specifically and should not be assumed for the OCC recertification exam.
Yes. Even though domains like Sarcoidosis and Bronchiectasis/cystic fibrosis sit at only 1-3%, there are nine domains in that narrow range collectively, and skipping them leaves meaningful points on the table.