- What the 14 Content Areas Really Are
- Exam Format and Registration Mechanics
- Clinical Foundations: Domains 1 and 2
- Billing Rules and Compliance: Domains 3 through 9
- ICD-10-CM Coding: Domain 10
- E/M Code Selection: Domain 11
- CPT Coding for Common Procedures: Domain 12
- Modifiers and HCPCS Level II: Domains 13 and 14
- Sequencing the 14 Areas Across Your Prep
- Code Books and Exam-Day Reference Rules
- Where These Skills Get Used
- Frequently Asked Questions
- The 14 CHONC content areas come from AAPC's 2026 study guide sample competency list, not an official weighted blueprint.
- The live exam is 100 multiple-choice questions in four hours; 70 correct answers (70%) passes.
- Active AAPC membership is required, and CPC or COC credentials are not prerequisites.
- Approved CPT, ICD-10-CM and HCPCS Level II books are allowed, so training should focus on fast, accurate lookup.
What the 14 Content Areas Really Are
The Certified Hematology and Oncology Coder (CHONC) credential is issued by AAPC. When people search for "CHONC exam domains," they usually expect a numbered blueprint with a percentage beside each domain. That is not what AAPC publishes for this exam. The official 2026 guide materials describe competencies and guide chapters, but they do not provide a current weighted domain list, and the largest content area is not publicly identified.
The 14 areas in this article are the top-level competency bullets printed on page 2 of the current AAPC CHONC Study Guide sample. They are published, exam-related competencies. They are not official weighted examination domains, and nothing here should be read as a promise of exhaustive exam coverage. The sample itself states that the guide is not comprehensive and that hands-on specialty coding experience matters.
For a broader plan built around this list, see our CHONC study guide for first-attempt success. This article goes deeper on what each competency demands.
Exam Format and Registration Mechanics
Knowing the container helps you interpret the content. The CHONC exam is delivered through Meazure Learning test centers, or remotely via ProctorU by Meazure Learning live proctoring. The structure is straightforward:
| Element | CHONC Detail |
|---|---|
| Questions | 100 multiple-choice |
| Time limit | 4 hours in one sitting |
| Passing standard | 70 correct, or 70% |
| Scored/unscored split | Not disclosed |
| Exam fee | USD 325 for one attempt; USD 399 for two attempts |
| Membership | Active AAPC membership required; observed add-on USD 229 |
| Prerequisites | CPC or COC not required; specialty experience recommended |
A candidate needs a valid ID, active membership and examination authorization. There is no non-member, exam-only eligibility tier, so budget for membership alongside the exam fee. Our CHONC certification cost breakdown walks through the combinations, and CHONC requirements and eligibility covers who can sit for it.
One caution: the study guide includes a 35-question exercise, and AAPC sells a 50-question practice product. Neither mirrors the live 100-question exam. Don't use them to calibrate pacing or score expectations. The CHONC-specific pass rate is not publicly disclosed, which we discuss in our CHONC pass rate analysis. For the scoring threshold itself, see what you need to pass.
Clinical Foundations: Domains 1 and 2
Domain 1: Medical terminology and anatomy
Hematology and oncology documentation is dense with specialty vocabulary. You must decode a note quickly enough to choose the right code.
- Cell lineage and blood component terminology (myeloid, lymphoid, platelets, plasma)
- Cancer site, laterality and morphology language that drives ICD-10-CM specificity
- Infusion, injection and biopsy vocabulary that separates one CPT family from another
- Anatomical locations of lymph nodes, marrow sites and organs commonly involved in staging
Domain 2: Medical physiology
Physiology explains why services are ordered and why diagnoses link to them. Expect questions where understanding the clinical picture helps you pick the defensible code.
- Normal and abnormal hematopoiesis and what treatments target
- Disease processes behind anemias, clotting disorders and malignancies
- How chemotherapy, immunotherapy and supportive care relate to the conditions treated
These two areas are the base layer. Candidates with strong terminology skills tend to read coding scenarios faster, which matters when you have four hours for 100 questions and a code book to consult.
Billing Rules and Compliance: Domains 3 through 9
Domains 3 through 9 cover the rules that determine who can bill, how, and under what documentation. Oncology practices face these rules daily because of high drug costs, shared care teams and research activity.
Domain 3: Teaching physician guidelines
When residents or fellows participate in care, billing depends on the teaching physician's documented presence and participation.
- What the teaching physician must personally perform or witness
- Documentation that supports billing under the teaching physician rules
Domain 4: Incident-to guidelines
Oncology clinics commonly involve nurse practitioners, physician assistants and nursing staff. Incident-to billing rules determine when services can be billed under the supervising physician.
- Supervision requirements and the established plan of care
- Situations where incident-to does not apply, such as new problems
Domain 5: Split/Shared services
Split/shared visits involve a physician and a non-physician practitioner in the same encounter. Candidates need to know which settings qualify and how the billing practitioner is identified.
Domain 6: HIPAA regulations
Expect privacy and security scenarios grounded in coding workflows: minimum necessary use, patient authorization and appropriate disclosure.
Domain 7: Proper use of the Advance Beneficiary Notice (ABN)
The ABN protects the patient's right to know about likely noncoverage before receiving a service. Know when it is appropriate, when it is not, and what makes one valid.
Domain 8: CMS drug wastage policy
Oncology drugs often come in single-dose vials where the dose given is less than the vial. Understand how wastage is reported and the documentation that supports it.
Domain 9: Clinical trial services
Research participation changes how services are billed. Candidates should distinguish routine care from items sponsored by a study, and understand the reporting conventions that flag trial-related services.
ICD-10-CM Coding: Domain 10
Diagnosis coding is where oncology specificity pays off. The study guide's published table of contents supplies additional diagnostic detail, but the sample is not the full paid guide, so confirm scope against the official materials you purchase.
Domain 10: ICD-10-CM coding
You must apply current official ICD-10-CM conventions and guidelines to documentation drawn from operative and physician notes.
- Neoplasm coding: primary versus secondary sites, and the guideline logic for sequencing
- Active malignancy versus personal history of malignancy
- Hematologic disorders and how specificity affects code selection
- Encounter reasons tied to treatment, such as chemotherapy or immunotherapy visits
- Using the Index, Tabular List and chapter-specific guidelines together
Because the exam permits approved ICD-10-CM references, a winning habit is practicing the lookup path: Index to Tabular to guideline check. Candidates who skip the Tabular verification step lose points on notes and excludes instructions.
E/M Code Selection: Domain 11
Domain 11: E/M code selection using the AMA CPT E/M guidelines
Evaluation and management coding is central to oncology office and hospital work. The area calls for selecting levels using the AMA CPT E/M guidelines.
- Choosing a level by medical decision making or by total time, as the guidelines allow
- Recognizing oncology complexity markers such as drug therapy requiring intensive monitoring for toxicity
- Telling new from established patients, and office from hospital or other settings
The exam rules allow a provided online E/M calculator, which differs from a prohibited personal calculator. Practice using the provided tool's logic rather than relying on a device you cannot bring into the session.
Key Takeaway
Build a repeatable E/M routine: identify setting and patient status, assess the three medical decision making elements, then check whether time is a better path. Doing it the same way every time protects you from rushing late in a four-hour session.
CPT Coding for Common Procedures: Domain 12
This competency keeps all five published subtopics from the study guide sample. The breadth is the challenge: oncology coding crosses several CPT sections in a single patient encounter.
Domain 12: CPT coding for common procedures
- 30000 Series: procedures in the respiratory and related surgical ranges encountered in specialty care
- Laboratory and Pathology: the testing and interpretation services central to hematology workups
- Radiology: imaging used for staging, monitoring and procedural guidance
- Medicine: a major home for chemotherapy administration and related infusion and injection services
- Category III codes: temporary codes for emerging technologies and services
The Medicine section deserves extra time because it carries the administration codes that define oncology infusion practices. Learn the hierarchy rules for infusion versus injection, initial versus sequential services, and the documentation (start and stop times) that supports them. Candidates working from operative and physician notes should practice extracting exactly which service was performed before selecting a code.
Modifiers and HCPCS Level II: Domains 13 and 14
Domain 13: CPT and HCPCS Level II modifier usage
Modifiers explain circumstances that change how a code is paid or interpreted.
- When a modifier is warranted by documentation versus merely available
- Modifiers affecting same-day services, bilateral or multiple procedures, and professional versus technical components
- HCPCS Level II modifiers commonly tied to drug wastage and other policy-driven reporting
Domain 14: HCPCS Level II coding
Many hematology and oncology drugs are reported with HCPCS Level II J-codes rather than CPT.
- Selecting the code that matches the specific drug and unit of measure
- Calculating billing units from the dose administered
- Connecting wastage reporting (Domain 8) to the correct code and modifier
Notice how Domains 8, 13 and 14 interlock. A single scenario can ask you to pick the drug code, compute units and apply the right wastage modifier. Studying them together reflects how the work actually happens.
Sequencing the 14 Areas Across Your Prep
Because no official weights exist, sequence by dependency rather than by percentage. Clinical language first, policy rules second, code-set mechanics third, then integration. This is the one place a timeline helps, and it is tied to the actual areas.
Foundations (Domains 1, 2)
- Build hematology and oncology vocabulary and physiology notes
- Annotate your code books with approved tabs
Rules and compliance (Domains 3-9)
- Work teaching physician, incident-to and split/shared together as one billing-authority cluster
- Review HIPAA, ABN, drug wastage and clinical trial rules
Diagnosis and E/M (Domains 10, 11)
- Practice neoplasm and hematologic coding from sample notes
- Drill E/M level selection under the AMA guidelines
Procedures, modifiers, HCPCS (Domains 12-14)
- Cover all five CPT subtopics, with extra time on Medicine
- Run combined drug, unit and modifier scenarios
Adjust the pacing to your experience. A coder already fluent in oncology E/M can compress the later weeks, while someone new to the specialty may need longer on the first two. Our CHONC cheat sheet can serve as a final-week review, and how hard the CHONC exam is helps you gauge how much time to allow. For timed scenario practice that mirrors the multiple-choice style, use the CHONC practice tests.
Code Books and Exam-Day Reference Rules
The CHONC permits approved CPT Professional, ICD-10-CM and HCPCS Level II references under current print and electronic rules. A study guide is not allowed in the testing session. Live proctoring and equipment requirements apply, which matters most for remote candidates.
- Use the current-year editions of every code set; outdated books create avoidable misses.
- Practice looking up codes under time limits, since four hours for 100 questions leaves room but not unlimited room.
- Confirm remote proctoring equipment and room requirements well before your appointment.
- Check scheduling windows in our guide to CHONC exam dates and scheduling.
Where These Skills Get Used
The 14 areas map to the daily work of specialty practices: hematology and oncology physician groups, cancer centers, hospital outpatient infusion departments, and billing companies that serve oncology clients. Teaching physician rules matter in academic settings, while incident-to and split/shared knowledge matters in advanced practice provider-heavy clinics. Drug wastage and clinical trial billing are close to universal in oncology revenue cycle work.
Whether the credential pays off financially is a separate question. No verified 2026 CHONC salary premium exists, so evaluate it using our salary analysis and the ROI discussion rather than relying on any quoted figure. Browse CHONC jobs to see how employers describe the specialty.
After certification, maintain the credential with annual AAPC membership and 36 CEUs per two-year cycle for one credential, including eight hematology/oncology CEUs. Totals differ if you hold multiple credentials. Candidates who want the full overview can start with what CHONC certification is, and anyone confused by the acronym should read what CHONC stands for. Return to the complete domain guide any time you want to recheck the list.
Frequently Asked Questions
No. The 14 areas come from the top-level competency bullets in AAPC's 2026 CHONC Study Guide sample. They are published competencies, not official weighted exam domains, and the largest content area is not publicly identified.
The exam has 100 multiple-choice questions over four hours in one sitting. Passing requires 70 correct answers, or 70%. The scored versus unscored split is not disclosed.
No. CPC or COC is not a prerequisite. You do need active AAPC membership, a valid ID and examination authorization. Specialty experience is recommended but no mandatory degree or training-hour total was verified.
Approved CPT Professional, ICD-10-CM and HCPCS Level II references are allowed under current print and electronic rules. A study guide is not allowed, and a provided online E/M calculator differs from a prohibited personal calculator.
Maintain annual AAPC membership and earn 36 CEUs per two-year cycle for a single credential, including eight hematology/oncology CEUs. Requirements for holders of multiple credentials vary.