- The 2026 Blueprint: Two Components, 23 Shared Domains
- Domain 1 & Domain 2: The Perinatal Pathology Core
- Domains 3-19: The Organ System Content Areas
- Domains 20-23: Procedures, Management, and Forensics
- Full Domain Weighting Table
- How Domains Show Up in the Question Format
- Sequencing 23 Domains Into a Study Plan
- Registration and Fee Mechanics Tied to Content Coverage
- Frequently Asked Questions
- The 2026 PP blueprint has 23 shared domain headings split across two separately weighted components.
- Fetal/Neonatal Pathophysiology (Domain 2) is the largest Written/Practical category at 15%.
- Every perinatal domain carries 10% weight in the Virtual Microscopy component.
- The exam totals 235 questions across 170 written/practical and 65 virtual-microscopy items.
The 2026 Blueprint: Two Components, 23 Shared Domains
The American Board of Pathology structures the Certification in Pathology: Pediatric Pathology (PP) exam around a content specification with an internal revision date of October 13, 2025. That document lists 23 shared domain headings, but it deliberately does not publish a single combined percentage for each domain. Instead, every domain carries two separate weights: one for the Written/Practical component and one for the Virtual Microscopy component. Candidates who try to average these two numbers into a single "importance score" are working from a misunderstanding of how the blueprint is built - the two distributions are intentionally kept apart.
This matters practically. A domain that looks modest in the written section can carry meaningfully more weight on the microscopy side, and vice versa. Building a study plan around only one column of numbers means under-preparing for the other 3 hours and 15 minutes of the exam. This guide walks through all 23 domains as grouped by the blueprint itself, then lays out the full weighting table so you can plan proportionally rather than by instinct.
Domain 1 & Domain 2: The Perinatal Pathology Core
The blueprint opens with two perinatal domains, and together they anchor the exam more heavily than any other pairing on the list.
Domain 1: Perinatal Pathology - Placental-Maternal-Fetal Relationships in Pregnancy
This domain covers the placenta as the interface between maternal and fetal physiology, including pathology that reflects maternal vascular disease, infection, and multiple gestation complications.
- Weighted at 7% Written/Practical and 10% Virtual Microscopy
- Placental lesions are a natural fit for image-based virtual microscopy items
Domain 2: Perinatal Pathology - Fetal/Neonatal Pathophysiology
This is the single largest Written/Practical category on the entire blueprint at 15%, and it also carries 10% on the Virtual Microscopy side. Candidates should treat this as the anchor topic of their preparation.
- Covers fetal and neonatal disease processes distinct from placental pathology itself
- Given its 15% written weight, this domain likely deserves more dedicated review time than any other single heading
Key Takeaway
If you only reorganize one part of your study plan after reading this article, make it this: allocate extra written-question review time to Domain 2, since 15% is the highest single Written/Practical weight in the blueprint.
Domains 3-19: The Organ System Content Areas
After the perinatal core, the blueprint moves through general pathologic principles and then organ-by-organ systems, mirroring the way pediatric pathology practice is organized in most fellowship programs and community-hospital sign-out.
Domain 3: General Pathologic Principles and Syndromes
Weighted 5% Written/Practical and 5% Virtual Microscopy, this domain covers cross-cutting concepts and recognized pediatric syndromes that appear across multiple organ systems.
Domain 4: Cardiovascular System
Weighted 6% Written/Practical and 3% Virtual Microscopy. Congenital heart disease pathology and vascular anomalies in the pediatric population are the natural focal points here.
Domain 5: Respiratory System and Mediastinum
Weighted 6% Written/Practical and 6% Virtual Microscopy, this domain balances evenly between the two components, making it a good candidate for combined-format review sessions.
Domain 6: Central Nervous System
Weighted 5% Written/Practical and 6% Virtual Microscopy. Pediatric CNS pathology carries distinct entities from adult neuropathology and deserves dedicated attention rather than assuming crossover from AP/CP training alone.
Domain 7: Skin
Weighted 3% Written/Practical and 5% Virtual Microscopy - notably higher on the microscopy side, which suggests image recognition of pediatric dermatopathology entities is emphasized relative to written recall.
Domain 8: Special Senses - Eye and Ear
The smallest domain on the written side at 1%, paired with 2% on Virtual Microscopy. Low weight, but not zero - a quick review pass is still worthwhile.
Domain 9: Alimentary Tract - GI
Weighted 7% Written/Practical and 8% Virtual Microscopy, this is one of the heavier mid-tier domains and deserves proportionally more study time than the single-digit domains around it.
Domain 10: Hepatobiliary System and Pancreas
Weighted 6% Written/Practical and 8% Virtual Microscopy. Pediatric liver disease and biliary atresia-spectrum pathology are classic high-yield topics under this heading.
Domain 11: Kidney and Urinary System
Weighted 5% Written/Practical and 6% Virtual Microscopy, covering pediatric renal pathology including developmental and glomerular disease.
Domain 12: Endocrine System, Excluding Ovary and Testis
Weighted 3% Written/Practical and 3% Virtual Microscopy, an evenly balanced but modest-weight domain.
Domain 13: Hematopoietic System
Including bone marrow, lymph nodes, thymus, spleen and other lymphoid tissues, this domain is weighted 6% Written/Practical and 9% Virtual Microscopy - one of the largest microscopy weights outside the perinatal core.
Domain 14: Breast
Weighted 1% Written/Practical and 2% Virtual Microscopy, one of the lowest-weight domains on the blueprint.
Domain 15: Female Reproductive System
Weighted 2% Written/Practical and 2% Virtual Microscopy.
Domain 16: Disorders of Sexual Development (Intersex Disorders)
Weighted 1% Written/Practical and 2% Virtual Microscopy. Small in weight but conceptually distinct enough to warrant a dedicated review session rather than folding it into general endocrine or reproductive study time.
Domain 17: Male Reproductive System
Weighted 1% Written/Practical and 2% Virtual Microscopy.
Domain 18: Soft Tissue, Peripheral Nerve and Muscle
Weighted 4% Written/Practical and 6% Virtual Microscopy - pediatric soft tissue tumors and muscle pathology are recognizably image-heavy, consistent with the higher microscopy weight.
Domain 19: Skeletal System
Weighted 3% Written/Practical and 3% Virtual Microscopy, covering pediatric bone pathology and developmental skeletal disease.
Domains 20-23: Procedures, Management, and Forensics
The final four domains shift away from organ-system disease and toward the practice of pediatric pathology itself - how specimens are handled, how a lab is run, and how forensic and administrative responsibilities intersect with day-to-day sign-out.
Domain 20: Diagnostic/Technical Procedures
Weighted 7% Written/Practical and only 2% Virtual Microscopy - a notable asymmetry. This suggests the domain is tested more through written scenario and procedure-based questions than through image interpretation.
Domain 21: Laboratory Management - Pediatric Pathology
Weighted 2% Written/Practical and 0% Virtual Microscopy, meaning this content is assessed exclusively in the written/practical component.
Domain 22: Forensic Pathology
Also weighted 2% Written/Practical and 0% Virtual Microscopy. Given its written-only presence, prioritize scenario-based recall over image study for this heading.
Domain 23: Management & Informatics - General
Weighted 2% Written/Practical and 0% Virtual Microscopy, closing out the blueprint with general administrative and informatics competencies relevant to running or participating in a pediatric pathology service.
Full Domain Weighting Table
Here is the complete approximate weighting for all 23 domains, kept as two separate distributions exactly as the blueprint presents them. Each column totals 100% on its own.
| Domain | Written/Practical % | Virtual Microscopy % |
|---|---|---|
| D1: Placental-Maternal-Fetal Relationships | 7% | 10% |
| D2: Fetal/Neonatal Pathophysiology | 15% | 10% |
| D3: General Pathologic Principles and Syndromes | 5% | 5% |
| D4: Cardiovascular System | 6% | 3% |
| D5: Respiratory System and Mediastinum | 6% | 6% |
| D6: Central Nervous System | 5% | 6% |
| D7: Skin | 3% | 5% |
| D8: Special Senses - Eye and Ear | 1% | 2% |
| D9: Alimentary Tract - GI | 7% | 8% |
| D10: Hepatobiliary System and Pancreas | 6% | 8% |
| D11: Kidney and Urinary System | 5% | 6% |
| D12: Endocrine System (excl. ovary/testis) | 3% | 3% |
| D13: Hematopoietic System | 6% | 9% |
| D14: Breast | 1% | 2% |
| D15: Female Reproductive System | 2% | 2% |
| D16: Disorders of Sexual Development | 1% | 2% |
| D17: Male Reproductive System | 1% | 2% |
| D18: Soft Tissue, Peripheral Nerve and Muscle | 4% | 6% |
| D19: Skeletal System | 3% | 3% |
| D20: Diagnostic/Technical Procedures | 7% | 2% |
| D21: Laboratory Management | 2% | 0% |
| D22: Forensic Pathology | 2% | 0% |
| D23: Management & Informatics - General | 2% | 0% |
How Domains Show Up in the Question Format
The PP exam is administered in person at Pearson VUE Professional Centers as a computer-based multiple-choice exam - it is not remotely proctored at home. The 2026 schedule breaks the testing day into six sections spread across two components: 170 written/practical questions in 3 hours 8 minutes, and 65 virtual-microscopy questions in 3 hours 15 minutes. That totals 235 scored questions and 6 hours 23 minutes of active testing, inside a scheduled day of 8 hours 53 minutes that also includes instructions, a survey, and breaks.
Because the virtual-microscopy component uses digital images rather than a glass-slide practical, every domain that carries a Virtual Microscopy percentage in the table above will appear as an image-based item during that 65-question block - not as a separate physical microscope station. Domains 21, 22, and 23, which carry 0% Virtual Microscopy weight, will only appear among the 170 written/practical questions.
Passing is determined by a scaled score of 500, not a percentage of raw questions answered correctly, so there is no fixed "number correct" target to aim for domain by domain. For a deeper breakdown of exactly what that scaled score means and how it's calculated, see the PP Passing Score 2026 guide.
Key Takeaway
Study the Virtual Microscopy weights separately from the Written/Practical weights - a domain like Domain 20 is written-heavy (7%) but nearly absent from microscopy (2%), while Domain 13 leans the opposite direction.
Sequencing 23 Domains Into a Study Plan
With 23 domains and two separate weight columns, the sequencing question isn't "what order feels natural" - it's which domains earn the most combined exposure across both components. A reasonable approach is to open your review with the perinatal core (Domains 1-2), since together they represent the single heaviest concentration of tested content, then move into the mid-weight organ systems (Domains 5, 9, 10, 11, 13), and finish with the low-weight but written-only administrative domains (21-23) as a final pass rather than an early priority.
Perinatal Core
- Domain 1: placental-maternal-fetal pathology, with emphasis on image recognition given its 10% microscopy weight
- Domain 2: fetal/neonatal pathophysiology, the single highest-weighted written domain at 15%
High-Volume Organ Systems
- Domain 9 (Alimentary Tract), Domain 10 (Hepatobiliary/Pancreas), Domain 13 (Hematopoietic System) - each carries 6-8% or higher on one or both components
- Pair written review with virtual-microscopy image sets for these domains specifically
Mid- and Lower-Weight Systems
- Cardiovascular, Respiratory, CNS, Kidney, Skin, Soft Tissue/Nerve/Muscle, Skeletal
- Move faster through Breast, Endocrine, Reproductive, DSD, and Special Senses given their 1-3% weights
Procedures and Administration
- Domain 20 (Diagnostic/Technical Procedures) reviewed as written-only content
- Domains 21-23 reviewed last, since none carry any Virtual Microscopy weight
For a more complete week-by-week framework that also covers eligibility timing and application deadlines, the PP Study Guide 2026 walks through the full preparation arc rather than just domain sequencing.
Registration and Fee Mechanics Tied to Content Coverage
Understanding the domains matters more once you see how the exam day is actually structured around them. The 2026 initial application/examination fee is USD 2,100, which includes a USD 200 nonrefundable administrative fee. That investment covers a single scheduled testing day built entirely around the 23-domain blueprint discussed above - there's no separate written-only or microscopy-only registration option.
Eligibility for sitting the exam requires primary certification in AP/CP or AP (or accepted Royal College of Physicians and Surgeons of Canada certification in Anatomic Pathology or General Pathology), plus 12 months of ACGME-accredited Pediatric Pathology fellowship training, along with applicable medical education, licensure, and training-verification requirements. If you're still confirming whether you meet these prerequisites, the PP Requirements 2026 guide covers eligibility in detail, and the PP Exam Dates 2026 guide covers testing windows and deadlines.
In 2025, all 17 examinees passed the exam, including all 13 first-time examinees - both reported pass rates were 100%, though from a small cohort. That context is worth keeping in mind when weighing how much domain-by-domain preparation actually matters versus overall readiness; the PP Pass Rate 2026 breakdown unpacks what these small-cohort numbers do and don't tell you.
Once you're comfortable with how the domains are weighted and tested, it helps to practice against realistic question formats before exam day. You can start building that familiarity now at the PP practice test platform, which mirrors the written and virtual-microscopy question styles described above. If you're earlier in the process and still deciding whether pursuing this subspecialty fits your career, Is the PP Certification Worth It? and PP Jobs are worth reading before you commit to the fee and fellowship timeline. And if any of this domain terminology