CPB Exam Prep: 135-Question Breakdown, Plan & Free Practice

The CPB is AAPC's Certified Professional Biller exam: 135 multiple-choice questions in four hours, and you need at least 95 right (70%). (AAPC exam details) Start your CPB exam prep with this original, unofficial case.

How to solve a case-analysis question

Source document: Northgate Health Plan, Therapy Benefit (fictional)

Physical therapy (PT) and occupational therapy (OT) visits share a combined limit of 20 visits per calendar year.

Visits beyond the limit require a medical-necessity review approved before the visit.

Visits over the limit without an approved review are denied as provider liability.

Question: By October 1, 2026, a Northgate member has had 13 PT visits and 7 OT visits this year. She has a PT visit on October 8. No review was requested. How should that claim be expected to process?

A. Paid, because she has used only 13 PT visits
B. Denied, and the member is billed for the visit
C. Denied as over the combined limit without an approved review, with the provider liable
D. Paid as an OT visit, since OT has visits left

Work it in four steps

Read the question first. You need two things: paid or denied, and who owes.
Find the rule. Item 1 says the limit is combined. Item 3 says who is liable.
Check the facts against it. 13 + 7 = 20 visits used, so October 8 is visit 21. No review was approved before the visit.
Eliminate. A ignores "combined." D invents a reclassification the policy doesn't allow. B contradicts item 3.

Answer: C. Answer by the document in front of you.

For any policy, real or on the exam, check these before you answer:

Payer and document: whose rule is it, and is it a policy, a contract, or a remittance?
Dates: which date controls (service date, claim date, notice date), and was the rule in effect then?
Conditions: what has to be true, such as authorization, setting, visit count, or deadline?
Liability: who pays if a condition isn't met?
Limits: what the document doesn't say. Don't fill gaps with another payer's rules.

AAPC gives you the source documents for the 34 cases, so you're tested on reading and applying a policy, not on memorizing it. (AAPC exam details)

Looking for a bookkeeping CPB (NACPB or CPB Canada)? This page covers AAPC's medical-billing exam.

Where the 135 questions come from

Nearly half the exam is insurance types and policy-reading cases. Only 10 questions are coding.

CPB exam question distribution across the seven AAPC areas, with share and required skills
Area	Questions	Share	What you need to be able to do
Case analysis	34	25%	Read a payer policy or other source document and apply it to a claim situation
Types of insurance	29	21%	Explain how Medicare, Medigap, Medicaid, managed care, commercial plans, Blue Cross/Blue Shield, TRICARE, workers' comp and auto or liability payers work, and who pays first
Reimbursement and collections	19	14%	Work with RBRVS, refunds, accounts receivable, patient statements, payment plans, collection agencies, bankruptcy, preauthorization, claim-editing tools and remittance advice
Claims and billing	19	14%	Handle denials, appeals, timely filing, claim follow-up, clean and electronic claims, balance billing and billing audits
Billing regulations	17	13%	Apply NCCI, LCDs and NCDs, incident-to billing, global packages, unbundling, CMS-1500 and UB-04 completion, ACOs and payer payment policies
Coding	10	7%	Use CPT, ICD-10-CM and HCPCS Level II codes and modifiers correctly
HIPAA and compliance	7	5%	Apply HIPAA privacy, billing compliance, record retention, financial policies, and fraud and abuse rules

Source: AAPC, Taking the CPB exam. Shares are rounded.

Put your hours where the questions are. Case analysis and insurance types together make up 63 questions. You can miss only 40 questions in total and still pass. If you're coming from the CPC, notice the shift: code look-ups are a small slice, and payer rules carry this exam.

CPB exam at a glance

CPB exam at a glance: current rules for each exam detail
Exam detail	Current rule
Questions	135 multiple choice, including the 34 case-analysis questions
Time	4 hours in one sitting, about 1 minute 47 seconds per question on average
Passing	70%, which AAPC states as at least 95 correct
Where	Online with a live remote proctor, or on a computer at a testing center
Code books	AMA's CPT Professional Edition, plus ICD-10-CM and HCPCS Level II from any publisher. One copy of each.
Book years	Current or preceding year, or a mix. Older books and next year's books aren't allowed.
Book format	Print or AAPC eBooks, chosen when you redeem your voucher. eBooks are searchable but carry none of your own notes.
To sit for it	Current AAPC membership, a current email and valid address on file, a valid unused exam voucher, and a government photo ID whose name exactly matches your exam confirmation
Prerequisites	The CPB is a stand-alone credential, so you don't need a CPC first. AAPC sets no minimum experience but highly recommends two years in the field.
Price	Standard exam pricing: $425 for one attempt or $499 for two attempts
Keeping it	Annual AAPC membership; 36 CEUs every two years when CPB is your only AAPC credential. Multiple credentials have different totals, and the first reporting period may be prorated.

If you see a 200-question, 5-hour-40-minute CPB described elsewhere, that's an old format. (AAPC's historical examinee instructions)

Sources: AAPC CPB certification; AAPC exam pricing; AAPC CEU and membership requirements; AAPC: which years' books to use; AAPC: book formats; AAPC: registration prerequisites.

Ready to book? Use our AAPC exam registration guide.

Billing rules to know cold

This is the core of what the exam asks you to apply. Each rule links to the official source it comes from. The practice questions further down test most of them.

Types of insurance

Billing rules to know: types of insurance situations and payer rules
Situation	Rule
Patient 65+ with group coverage from their own or a spouse's current job	Employer has 20 or more employees: the group plan pays first, Medicare second. For a single-employer plan with fewer than 20, Medicare generally pays first. Multi-employer plans can have different rules; check the plan's payer order. (Medicare.gov, Who pays first?)
Work-related injury	Workers' comp pays first for services related to the claim. (Medicare.gov, Who pays first?)
Medicare and Medicaid	Medicaid never pays first for services Medicare covers. Medicaid is generally the payer of last resort. (Medicare.gov, Who pays first?)
Medigap	It supplements Original Medicare and can't pay Medicare Advantage copayments, deductibles or premiums. Most existing Medigap policies do not automatically cancel when someone joins Medicare Advantage. (Medicare.gov, How Medigap works)

Billing regulations

Billing rules to know: billing regulations topics and rules
Topic	Rule
NCD vs LCD	CMS issues National Coverage Determinations, which apply in every state. A Medicare Administrative Contractor (MAC) issues Local Coverage Determinations for its own jurisdiction. An LCD can't contradict an NCD. (CMS, Coverage Document Type Descriptions)
Medicare NCCI procedure-to-procedure edits	Modifier indicator 0: no NCCI-associated modifier can bypass the edit. 1: an NCCI-associated modifier is allowed when the documented circumstances fit. 9: no active edit. (CMS MLN901346, Ch. 2, Table 1)
ABN	For Original Medicare, give a valid Advance Beneficiary Notice before the service when an ABN is required to transfer liability for an expected denial. GA = ABN issued as required. GZ = medical-necessity denial expected, no ABN. GY = statutorily excluded or outside any Medicare benefit. (CMS MLN006266, pp. 3, 6, 11)
Global surgery	0-day and 10-day postoperative periods for minor procedures, 90 days for major surgery. Modifier 24: unrelated E/M during the postoperative period. 25: significant, separately identifiable E/M beyond the usual procedure work on the day of a procedure. 57: the first decision for major surgery at an E/M on the day before or day of surgery. (CMS MLN907166, pp. 4, 9–10, 13)

HIPAA and compliance

Billing rules to know: HIPAA and compliance topics and rules
Topic	Rule
Minimum necessary	Limit uses and disclosures to what the purpose needs. Exceptions include disclosures to a provider for treatment, disclosures to the patient, and disclosures made with the patient's authorization. (HHS, Minimum Necessary Requirement)
Self-pay restriction	If a patient pays in full out of pocket and asks a HIPAA-covered entity not to disclose information solely about that service to their health plan for payment or health care operations, the entity must agree, unless a law requires the disclosure. (45 CFR 164.522(a)(1)(vi))

Reimbursement and collections

Billing rules to know: reimbursement and collections topics and rules
Topic	Rule
Deductible, then coinsurance	For a covered service subject to a deductible and coinsurance, apply the remaining deductible first, up to the allowed amount. Coinsurance is a percentage of what's left of the allowed amount. (HealthCare.gov, Coinsurance)
Medicare physician fee schedule	Fee-schedule amount before patient cost sharing and other payment adjustments = [(Work RVU × Work GPCI) + (PE RVU × PE GPCI) + (MP RVU × MP GPCI)] × conversion factor. (CMS, PFS Documentation and Files)
Nonparticipating physicians	For a covered physician service subject to the standard federal limiting charge, the nonparticipating fee schedule amount is 95% of the participating amount. On a nonassigned claim, the federal limiting charge is 115% of that nonparticipating amount. (CMS, PFS Documentation and Files)
Remittance group codes	CO (contractual obligation) puts the unpaid amount on the provider. PR (patient responsibility) puts it on the patient. A Medicare beneficiary can be billed only when an adjustment carries PR, but PR does not override other billing protections or amounts already paid. CARCs give the reason for an adjustment, and RARCs add detail. (CMS, Health Care Payment and Remittance Advice)
Collection calls	For an FDCPA-covered debt collector, calls before 8 a.m. or after 9 p.m. at the consumer's location are presumed inconvenient, absent an applicable exception. A known inconvenient time can also be prohibited within those hours. The definition includes many third-party collectors and has exclusions. (CFPB Regulation F, §1006.6(b); §1006.2(i))

Medicare's Qualified Medicare Beneficiary (QMB) protections prohibit billing QMBs for Medicare-covered Part A or Part B cost sharing. (CMS, QMB billing protections)

Claims and billing

Billing rules to know: claims and billing topics and rules
Topic	Rule
Medicare timely filing	The appropriate MAC must receive the claim no later than one calendar year after the date of service, unless a specified exception applies. (42 CFR 424.44)
Returned as unprocessable	When Medicare returns a claim as unprocessable for missing or invalid information, that return is not a denial and has no appeal rights. Correct and resubmit using the MAC's instructions. (CMS Claims Processing Manual, Ch. 1 §§80.3.1–80.3.2; First Coast, claims returned as unprocessable)
Medicare appeals	For an appealable Original Medicare Parts A/B determination, level 1 is a redetermination by the MAC, requested within 120 days of receiving the initial determination. Level 2 is a reconsideration by a Qualified Independent Contractor (QIC), within 180 days of receiving the redetermination. Receipt is presumed five days after the notice date unless evidence shows later receipt. (CMS MLN006562, pp. 6, 8)

Use the right form or transaction for the job:

Claims tasks matched to paper forms or electronic transactions
Task	Paper form or electronic transaction
Ask about eligibility and get the answer	270 request, 271 response (CMS, HETS 270/271)
Bill a professional (non-institutional) claim	CMS-1500 on paper, 837P electronically (CMS MLN006976, p. 3)
Bill an institutional claim, such as hospital facility charges	CMS-1450 (UB-04) on paper, 837I electronically (CMS MLN006926, p. 3)
Check a claim's status	276 request, 277 response (CMS, Claim Status Request and Response)
Receive payment and adjustment details	835 electronic remittance advice (CMS, Remittance Advice)

Coding

Code sets and what each is used for
Code set	Used for
ICD-10-CM	Diagnoses, in every health care setting
CPT (HCPCS Level I)	Procedures and services
HCPCS Level II	Products, supplies and services not in CPT
ICD-10-PCS	Inpatient hospital facility procedures. It isn't one of the CPB's approved books.

A valid code doesn't by itself mean the service is covered. (CMS, Overview of Coding and Classification Systems)

23 free CPB practice questions

These are original questions written by Castleport Test Prep, not AAPC exam items. Your score is feedback on these 23 questions only. It isn't a prediction of your exam result. The questions sample all seven AAPC areas; this short set does not reproduce the exam's proportions or full coverage.

Types of insurance

CPB-01. Ruth, 68, works full time for a company with 240 employees and is covered by its group health plan. She is also enrolled in Medicare Part B. Which payer should receive her office-visit claim first?

A. Medicare
B. The employer group health plan
C. Both at once, each paying half
D. Her Medigap policy

Show answer and explanation

Answer: B. When someone 65 or older has group coverage from current employment and the employer has 20 or more employees, the group plan pays first and Medicare pays second. A reverses the payer order in this situation. D is wrong because Medigap supplements Original Medicare; it isn't a primary payer. C isn't how coordination of benefits works: payers pay in order, not in shares.

Source: Medicare.gov, Who pays first?

CPB-02. A 66-year-old Medicare beneficiary who works part time hurts his back lifting boxes at work. His employer's workers' compensation carrier has accepted the claim. Which payer should be billed first for treatment of that injury?

A. Medicare Part B
B. Medicaid
C. The patient, until the workers' comp claim closes
D. The workers' compensation carrier

Show answer and explanation

Answer: D. Workers' compensation pays first for services related to the work injury. A is wrong because Medicare doesn't pay first for services covered by the workers' comp claim. C skips the payer that's responsible. B is wrong because Medicaid doesn't pay ahead of other coverage.

Source: Medicare.gov, Who pays first?

CPB-03. A patient has both Original Medicare and full Medicaid, with no other coverage. She receives a service Medicare covers. Which payer is primary, and which follows it?

A. Medicare, then Medicaid
B. Medicaid, then Medicare
C. Medicaid only
D. Whichever order the patient chooses

Show answer and explanation

Answer: A. Medicaid never pays first for services Medicare covers, and it's generally the payer of last resort. B reverses that order. C leaves out Medicare, which pays first. D is wrong because payer order is set by rules, not by patient preference.

Sources: Medicare.gov, Who pays first?

CPB-04. A patient enrolled in a Medicare Advantage plan hands the front desk a Medigap card and asks you to bill it for her Medicare Advantage copayment. What's accurate?

A. Bill Medigap as secondary to the Medicare Advantage plan
B. Bill Medigap first, then the Medicare Advantage plan
C. Bill Original Medicare instead of the Medicare Advantage plan
D. Don't bill Medigap for this Medicare Advantage copayment

Show answer and explanation

Answer: D. Medigap is a supplement to Original Medicare. Medicare.gov says you can't use Medigap to pay Medicare Advantage copayments. Most existing Medigap policies do not automatically cancel when someone joins Medicare Advantage. A and B treat Medigap as if it coordinates with Medicare Advantage. C does not resolve this Medicare Advantage copayment.

Source: Medicare.gov, How Medigap works

Billing regulations

CPB-05. For an Original Medicare claim, two procedures performed by the same physician for the same patient on the same date are subject to an active NCCI procedure-to-procedure edit with a modifier indicator of 0. A coworker suggests adding modifier 59 to the column 2 code. What's correct?

A. Add modifier 59 and submit
B. Use modifier XS instead of 59
C. No NCCI-associated modifier can bypass this edit
D. Submit the two codes on separate claims

Show answer and explanation

Answer: C. Modifier indicator 0 means no NCCI-associated modifier can bypass the edit. With indicator 1, a modifier is allowed, but only when the documented circumstances actually fit. Indicator 9 means there's no active edit. A and B try modifiers this edit doesn't permit. D splits claims to get around an edit, which is exactly the unbundling NCCI exists to stop.

Source: CMS MLN901346, How to Use the Medicare NCCI Tools, Ch. 2, Table 1

CPB-06. A provider expects Original Medicare Part B to deny a service as not reasonable and necessary at the frequency the patient wants. A valid, required ABN was issued and signed before the service. The patient chose to receive the service and have the claim submitted to Medicare. Which modifier goes on the claim line?

A. GZ
B. 25
C. GY
D. GA

Show answer and explanation

Answer: D. GA reports that a required waiver-of-liability statement, the ABN, was issued. GZ is for an expected medical-necessity denial with no ABN on file. GY is for statutorily excluded items or services outside any Medicare benefit. Modifier 25 is an E/M modifier and has nothing to do with liability notices.

Source: CMS MLN006266, Medicare Advance Written Notices of Non-coverage, pp. 6, 11

CPB-07. A surgeon performs a major procedure with a 90-day global period on June 2. On June 20 the same surgeon sees the patient for a new problem unrelated to the surgery. Which modifier goes on the E/M service?

A. 24
B. 25
C. 57
D. GA

Show answer and explanation

Answer: A. Modifier 24 reports an unrelated E/M by the same provider during a postoperative period. Modifier 25 is for a significant, separately identifiable E/M on the same day as a procedure. Modifier 57 marks an E/M on the day before or day of major surgery at which the first decision for that surgery was made. GA is a liability-notice modifier.

Source: CMS MLN907166, Global Surgery Booklet, pp. 4, 9–10, 13

HIPAA and compliance

CPB-08. Which disclosure is not subject to HIPAA's minimum necessary standard? Assume no individual authorization or other applicable exception removes the requirement from the payment or operations disclosures.

A. Sending documentation to a payer to support an appeal
B. Giving account details to the practice's collection agency
C. Sending a patient's records to a specialist who is treating the patient
D. Sending records to a health plan for its claim audit

Show answer and explanation

Answer: C. The minimum necessary standard doesn't apply to disclosures to a health care provider for treatment. A, B and D are payment or operations disclosures, so the practice should limit what it sends to what that purpose needs.

Source: HHS, Minimum Necessary Requirement

CPB-09. A patient pays $400 in full, out of pocket, for a service at a HIPAA-covered practice and asks the practice not to send information solely about it to her health plan for payment or health care operations. No law requires the disclosure. What must the practice do?

A. Agree to the restriction
B. Decide case by case whether to agree
C. Refuse, because health plans may audit any service
D. Agree only if the provider is out of network

Show answer and explanation

Answer: A. HIPAA requires a covered entity to agree to this restriction when the disclosure would be for payment or health care operations, isn't required by law, pertains solely to the service, and the service was paid in full by someone other than the health plan. Most restriction requests are optional for the practice, which is what makes B tempting, but this one isn't. C and D add conditions the rule doesn't contain.

Source: 45 CFR 164.522(a)(1)(vi)

Reimbursement and collections

CPB-10. A covered, in-network service has an allowed amount of $220. The patient has $50 of her deductible left, then owes 20% coinsurance. There's no copay, no secondary coverage, and no out-of-pocket maximum in play. What does the patient owe for this service?

A. $44
B. $84
C. $94
D. $220

Show answer and explanation

Answer: B. Apply the deductible first: $220 − $50 = $170 left. Coinsurance is 20% × $170 = $34. The patient owes $50 + $34 = $84, and the plan pays $136. A takes 20% of the full allowed amount and skips the deductible. C adds the deductible to 20% of the full $220, so it charges coinsurance on the $50 deductible too. D ignores the plan's share.

Source: HealthCare.gov, Coinsurance

CPB-11. Using Medicare's physician fee schedule formula and the values below, what's the fee-schedule amount before patient cost sharing and other payment adjustments?

Work RVU 1.50, work GPCI 1.02
PE RVU 1.10, PE GPCI 0.95
MP RVU 0.10, MP GPCI 1.10
Conversion factor $34.00 (example value)

A. $52.02
B. $91.29
C. $91.80
D. $2.69

Show answer and explanation

Answer: B. Multiply each RVU by its GPCI, add, then multiply by the conversion factor: (1.50 × 1.02) + (1.10 × 0.95) + (0.10 × 1.10) = 1.53 + 1.045 + 0.11 = 2.685, and 2.685 × $34.00 = $91.29. A uses only the work component. C skips the GPCIs (2.70 × $34.00). D forgets the conversion factor. The real conversion factor changes every year; for 2026, CMS set two of them, rounded here to cents: $33.57 for qualifying APM participants and $33.40 for everyone else.

Sources: CMS, PFS Documentation and Files; CMS CY 2026 PFS final rule fact sheet

CPB-12. The Medicare participating fee schedule amount for a covered physician service is $120.00. The service is subject to the standard federal limiting charge, with no stricter applicable state limit. What's the limiting charge for a nonparticipating physician who doesn't accept assignment?

A. $114.00
B. $126.00
C. $131.10
D. $138.00

Show answer and explanation

Answer: C. The nonparticipating fee schedule amount is 95% of the participating amount, which is $114.00. The limiting charge is 115% of that: $114.00 × 1.15 = $131.10. A stops at the nonparticipating amount. D applies 115% to the participating amount, a common mistake. B doesn't come from either rule.

Source: CMS, PFS Documentation and Files

CPB-13. An FDCPA-covered third-party collection agency hired by a practice calls a patient about an overdue balance at 7:15 a.m. her local time. Nothing tells the agency that this hour is convenient for her, and neither consumer consent nor court permission authorizes the early call. What's the issue?

A. It's outside the hours the FDCPA presumes convenient
B. None, because the practice authorized the agency
C. None, because weekday calls are always allowed
D. The FDCPA bars all phone contact about medical debt

Show answer and explanation

Answer: A. Absent an applicable exception, a debt collector's call before 8 a.m. or after 9 p.m. at the consumer's location is presumed inconvenient. This agency is expressly covered by the FDCPA. B and C ignore that rule. D overstates it: calls are allowed within the rules.

Sources: CFPB Regulation F, §1006.6(b)(1), (4); §1006.2(i)

Claims and billing

CPB-14. A Medicare Part B service was performed on March 10, 2026. Under Medicare's standard timely-filing rule, what's the last day the appropriate MAC can receive the claim?

A. September 6, 2026
B. December 31, 2026
C. March 10, 2027
D. December 31, 2027

Show answer and explanation

Answer: C. Under the standard rule, the appropriate MAC must receive Medicare claims no later than one calendar year after the date of service. A is a 180-day count, which isn't Medicare's rule. D extends beyond the standard one-calendar-year limit. B isn't a Medicare deadline.

Source: 42 CFR 424.44(a)(1)

CPB-15. An assigned Original Medicare Part B claim is denied for a coverage reason in the initial determination. The provider is entitled to appeal and disagrees. What's the first level of appeal, and how long is there to request it?

A. QIC reconsideration, within 180 days
B. MAC redetermination, within 120 days of receiving the initial determination
C. Administrative law judge hearing
D. Resubmit as a corrected claim within one year

Show answer and explanation

Answer: B. The first level is a redetermination by the Medicare Administrative Contractor, requested within 120 days of receiving the initial determination. Receipt is presumed five days after the notice date unless evidence shows later receipt. A is the second level, after a redetermination. C comes later still. D fixes billing errors; it isn't an appeal of a coverage decision.

Source: CMS MLN006562, Medicare Parts A & B Appeals Process, pp. 6, 8

CPB-16. An Original Medicare Part B professional claim comes back on the remittance advice as returned as unprocessable because a required field was invalid. What's the right next step?

A. Request a redetermination within 120 days
B. Bill the patient for the full charge
C. Resubmit the same claim unchanged
D. Correct the information and submit a new claim

Show answer and explanation

Answer: D. A claim returned as unprocessable hasn't been denied, and it carries no appeal rights. Fix the incomplete or invalid information and submit a new claim. A treats it as a denial, which only delays payment and can push you past timely filing. C repeats the error. B shifts the cost to a patient who isn't responsible for a claim error.

Sources: CMS Claims Processing Manual, Ch. 1 §§80.3.1–80.3.2; First Coast, What you should do with claims returned as unprocessable

CPB-17. A patient has outpatient surgery in a hospital. Which paper claim form corresponds to the hospital's facility charges?

A. UB-04 (CMS-1450)
B. CMS-1500
C. ADA dental claim form
D. The surgeon's superbill

Show answer and explanation

Answer: A. Institutional providers bill on the UB-04 (CMS-1450) or its electronic version, the 837I. The CMS-1500 (837P) is for professional, non-institutional claims, such as the surgeon's own fee. C is for dental services. D is an internal charge document, not a claim.

Sources: CMS MLN006976, CMS-1500 & 837P, p. 3; CMS MLN006926, CMS-1450 & 837I, p. 3

Coding

CPB-18. At one visit, a physician evaluates a patient's new, significant problem and, the same day, performs a minor procedure with a 10-day global period for a different issue. The medically necessary E/M is separately documented and significant and separately identifiable beyond the usual work of the minor procedure. Which modifier goes on the E/M?

A. 25
B. 24
C. 57
D. 59

Show answer and explanation

Answer: A. Modifier 25 reports a significant, separately identifiable E/M on the same day as a procedure. Modifier 24 is for an unrelated E/M later in the postoperative period. Modifier 57 marks the first decision for major surgery at an E/M on the day before or day of surgery, and this is a minor procedure. Modifier 59 is a procedure modifier, not the E/M modifier for this situation.

Source: CMS MLN907166, Global Surgery Booklet, pp. 10, 13

CPB-19. A practice supplies a patient with a pair of crutches and needs a code for the item. Which code set is built to report products and supplies like this?

A. ICD-10-CM
B. CPT
C. HCPCS Level II
D. ICD-10-PCS

Show answer and explanation

Answer: C. HCPCS Level II exists mainly to identify products, supplies and services that aren't in CPT. A reports diagnoses, not items. B (HCPCS Level I) covers procedures and services. D is for inpatient hospital facility procedures and isn't one of the CPB's approved books. Remember that finding a valid code doesn't mean the payer covers the item.

Source: CMS, Overview of Coding and Classification Systems

Case analysis

Source document 1: Northgate Health Plan, Outpatient Imaging Authorization (fictional)

Prior authorization is required before any nonemergency outpatient MRI or CT.

Retro-authorization may be requested within 2 business days after the service only when the service was performed in an emergency department.

Claims denied for missing authorization are provider liability. The member may not be billed for the denied service.

Appeals must be received within 60 calendar days of the date on the denial notice (day 1 is the day after that date) and must include the denial notice and supporting medical records.

CPB-20. A practice performed a nonemergency lumbar MRI in its own imaging suite on April 7 without authorization. The claim was denied on May 1 for no authorization. The front desk wants to request retro-authorization or bill the patient. Under this policy, what's correct?

A. Request retro-authorization within 2 business days of the denial
B. Bill the patient for the full charge
C. Retro-authorization isn't available, and the patient can't be billed
D. Rebill with modifier GA

Show answer and explanation

Answer: C. Item 2 limits retro-authorization to emergency department services, and its clock runs from the service date anyway. Item 3 makes the current denial provider liability and bars billing the member. Any appeal must follow item 4. A misreads both conditions. B violates item 3. D does not satisfy this policy's authorization requirement.

CPB-21. For the denial notice dated May 1, 2026, what's the last day Northgate can receive a timely appeal?

A. May 31, 2026
B. June 29, 2026
C. June 30, 2026
D. July 1, 2026

Show answer and explanation

Answer: C. Count 60 calendar days from May 1. May 2 through May 31 is 30 days, and June 1 through June 30 is 30 more, which lands on June 30. B and D are off by a day in each direction. A counts one month instead of 60 days. Item 4 says "received": the appeal must be received, not merely sent, by June 30.

Source document 2: Remittance advice excerpt, Northgate PPO (fictional)

Covered, in-network commercial PPO service. The $180 allowance matches the contract. There is no secondary coverage, other assistance or applicable collection restriction, and the patient has paid nothing toward this line.

Patient: J. Ortiz · Date of service: 08/12/2026 · Line 1

Billed $250.00 · Allowed $180.00 · Deductible $0.00 · Coinsurance $36.00 · Paid $144.00

Adjustments: CO-45 $70.00 · PR-2 $36.00

Legend: CO = contractual obligation (provider adjustment; not billable to the member under the participation agreement). PR = patient responsibility. 45 = charge exceeds fee schedule/maximum allowable or contracted fee. 2 = coinsurance amount.

The amounts and contract are fictional; the code meanings come from X12, Claim Adjustment Reason Codes, 2 and 45 and CMS, Remittance Advice.

CPB-22. How much can the practice bill J. Ortiz for this line?

A. $0.00
B. $36.00
C. $70.00
D. $106.00

Show answer and explanation

Answer: B. Only the PR adjustment is the patient's: the $36.00 coinsurance. C is the CO-45 amount, which the legend says can't be billed to the member. D adds both together. A ignores the coinsurance.

CPB-23. How should the $70.00 CO-45 adjustment be posted?

A. Transfer it to the patient's balance
B. Bill it to a secondary payer
C. Appeal it as a denial
D. Post it as a contractual write-off

Show answer and explanation

Answer: D. CO-45 says the charge exceeded the contracted allowance, so the difference is written off under the contract. A violates the legend. C doesn't fit because the supplied remittance identifies this $70 as a contractual adjustment, not a denial. Question the adjustment if the $180.00 allowed amount doesn't match the rate in your contract. B treats a contractual write-off as if another payer owed it.

Scoring your set

Count your correct answers, then group your misses by area. Any area where you missed half or more is a starting point for next week's study. With only two to four questions per area, treat that as a pointer, not a measurement.

Your CPB study plan

6-week plan

This plan is for people who have finished billing training or work in billing, studying about 8 hours a week. Insurance and case analysis, the two biggest areas, each get a full week. For weeks 1–5, use four 2-hour blocks each week: about 45 minutes reading, 30 minutes recalling the rule without looking, 30 minutes applying it, and 15 minutes updating your error log. These are adaptable study schedules, not a required hour count or a guarantee of readiness.

Six-week CPB study plan by week: focus, tasks and expected outcome
Week	Focus	Do this	You should finish with
1	Types of insurance	Study Medicare Parts A–D, Medicare as secondary payer, Medigap vs Medicare Advantage, Medicaid, TRICARE, workers' comp and liability. Use the insurance table and the Week 1 readings below. Answer CPB-01 to CPB-04.	A one-page "who pays first" sheet you can rebuild from memory
2	Billing regulations and coding	NCCI edits and modifier indicators, LCD vs NCD, ABNs, incident-to, global surgery, the code-set roles. Use the Week 2 readings below. If you already have your exam references, practice modifier and HCPCS look-ups in that format; otherwise use the linked CMS modifier and code-set explanations for this review. Answer CPB-05 to CPB-07, CPB-18 and CPB-19.	A modifier sheet covering 24, 25, 57, 59, GA, GZ and GY, each with one sentence on when it applies
3	Claims and billing, plus HIPAA	Timely filing, clean vs unprocessable claims, denial reasons, the appeal levels, balance billing, CMS-1500 vs UB-04; minimum necessary, restriction rights, fraud and abuse. Use the Week 3 readings below. Answer CPB-08, CPB-09 and CPB-14 to CPB-17.	The transaction table and the appeal levels written out from memory, then checked against the sources
4	Reimbursement and collections	Deductible and coinsurance math, the RBRVS formula, limiting charge, reading remittance advice, refunds, FDCPA basics, payment plans, preauthorization. Use the Week 4 readings below. Answer CPB-10 to CPB-13.	Three worked calculations of your own, each checked against its total
5	Case analysis	Rework the opening example, answer CPB-20 to CPB-23, and complete the three policy variations below. Use the five-point checklist to identify the controlling clause and explain why each wrong option fails. Spread the work across your four study blocks.	An error log entry for every case you miss
6	Consolidation and pacing	Complete the 4-hour review block below, then spend the other 4 hours on every miss, sorted by area. If you already have a lawful, unseen 135-question practice exam, you may use a 4-hour timed attempt instead of the review block.	Your final review list, sorted by area

Free readings for weeks 1–4

Use the rule tables and their linked sources first. These additional readings fill the topics named in the schedule:

Free readings and how to apply them in weeks 1 to 4
Week	Free reading	Apply it
1	Medicare's parts, who pays first, TRICARE 101, and TRICARE with other health insurance	Add the conditions and exceptions to your payer-order sheet; don't reduce every coordination rule to one universal order.
2	CMS incident-to requirements and proper use of modifiers 59, XE, XP, XS and XU, pp. 3–4	Write the conditions for incident-to billing and contrast a documented modifier exception with an attempt to bypass an edit.
3	CMS professional claim guide, CMS institutional claim guide, and HHS OIG fraud and abuse laws	Map the claim route and distinguish the conduct addressed by the False Claims Act, Anti-Kickback Statute and physician self-referral law. Focus on the conduct and conditions, not penalty amounts in older examples.
4	CMS Medicare overpayments, pp. 3–4 and CFPB on difficulty paying a medical bill	Trace a payment error through correction and follow-up. For a patient balance, list the bill checks, assistance questions and payment-plan questions to resolve before collection.

Three policy variations for week 5

These are unscored review drills, separate from the 23-question set. Use the same fictional documents; change only the facts stated here.

REVIEW-01 — Therapy approval. In the opening Northgate therapy case, the medical-necessity review was approved before visit 21. Does the over-limit clause alone require denial?

Answer: No. The approval meets the stated exception for visits beyond 20. That removes this specific reason for denial; the document does not establish that every other condition for payment is met.

REVIEW-02 — Appeal contents. For the May 1 imaging denial in source document 1, Northgate receives the appeal on June 30, 2026, with the denial notice but no supporting medical records. Has the practice met all of item 4's stated requirements?

Answer: No. June 30 is timely, but item 4 also requires the denial notice and supporting medical records. Meeting the deadline alone does not meet the document requirement.

REVIEW-03 — Changed remittance. In source document 2, coinsurance and PR-2 are $18 and the plan payment is $162; all other facts stay the same. What is the remaining patient balance, and does the line reconcile?

Answer: The patient balance is $18. The $70 CO-45 remains a contractual adjustment: $18 + $162 = $180 allowed, and $70 + $18 + $162 = $250 billed.

A 4-hour review block for week 6

Four-hour review block for week 6, minutes per task
Minutes	Task
40	Answer the 23 questions without looking at the explanations. If you have seen them already, treat this as retrieval practice, not a fresh assessment.
80	Review each rationale. For every miss or guess, explain the correct rule and why the distractors fail.
60	Choose two weak areas and read their exact official sources linked above. Add the controlling condition and source to your error log.
45	Rebuild the transaction table, recalculate CPB-10 to CPB-12, and work through the three policy variations. Check against the supplied answers.
15	Make the final review list from unresolved errors and missing knowledge.

This totals four hours of review; it is not a full-length practice exam. Repeated-item scores cannot tell you how you would perform on unseen questions.

10-week plan

This is for people newer to billing, at the same 8 hours a week. Add four weeks at the front. AAPC expects working knowledge of medical terminology, anatomy and pathophysiology alongside payer rules and the code sets. Spend weeks 1–2 on terminology and anatomy. Spend weeks 3–4 on the revenue cycle end to end: registration, eligibility, charge entry, the claim, payment posting and follow-up. Then run the 6-week plan.

Ten-week plan foundation weeks: four 2-hour blocks and expected outcome
Foundation week	Four 2-hour blocks	You should finish with
1	Work through MedlinePlus: Understanding Medical Words. Build 20 terms from prefixes, roots and suffixes, then explain them without looking. Use unfamiliar terms from this page for a second pass.	A terminology sheet with the parts and plain-language meaning of each term
2	Use NCI's anatomy and physiology modules and anatomical terminology. Review body systems and directional terms; record disease-process terms you still need to learn through your billing training.	A body-system map and a specific list of anatomy or pathophysiology gaps
3	Follow the on-page transaction table and CMS professional claim guide. Trace registration and eligibility through charge entry, submission, payment posting and follow-up.	One annotated claim-flow map showing the form or transaction at each step
4	Read the insurance rules, work the opening case, and use source documents 1 and 2 to identify authorization, allowance, adjustment and patient-responsibility conditions. Revisit the gaps logged in weeks 1–3 before beginning the six-week sequence.	A first error log and a clear list of topics requiring more training

The schedules total about 48 hours over six weeks or 80 hours over ten weeks. A beginner may need additional training and more time; the foundation weeks do not replace a billing course or establish exam readiness.

Adjusting either plan

Less time each week? Split each week across two calendar weeks rather than dropping topics.
Retaking? Start with the areas from your actual results and your error log, then work the remaining weeks in order. Retake rules are covered in our AAPC exam retake policy guide.
Keep one timed block every week from week 3 on. The clock is part of the test.
Don't skip case analysis because you know the rules. It's the largest area, and it rewards careful reading as much as knowledge.
Use only lawful practice material. Recalled or leaked exam questions are off-limits, and rereading answers you've already seen isn't a fresh test.

Turn each miss into a next step

Write down every miss in a log like this. A useful entry names the exact mistake and the rule, not "study harder."

Error log template for turning each miss into a next step
Question or task	What I chose	Exact error	Rule and source	Next action
Example: CPB-10	$94	Added the deductible to 20% of the full allowed amount, so coinsurance was charged on the deductible too	Deductible first, then coinsurance on what's left (HealthCare.gov)	Redo it: $50 + 20% × $170 = $84. Then write one new example with different numbers.

Exam day: books, pacing and setup

Your code books

Bring AMA's CPT Professional Edition, an ICD-10-CM and a HCPCS Level II book: current or preceding year, one copy each. Or choose AAPC eBooks when you redeem your voucher. You can switch formats up to 48 hours before the exam. eBooks are searchable but won't carry your own notes, so practice look-ups in the format you'll actually use. For HCPCS in 2026, exams before March 2 used the 2025 code set; from March 2 the exam uses the 2026 code set. Either the 2025 or 2026 print book is allowed under the current-or-preceding-year rule. If a second attempt falls in the next calendar year, you take that year's exam.

AAPC limits what you can write, tab or insert in your books, and it bars copying practice or exam questions into them. Check the current rules before you mark anything up.

Sources: AAPC: which years' books to use; AAPC: book formats; AAPC: Taking the CPB exam

With only 10 coding questions, don't let code look-ups crowd out insurance and policy practice. Include modifier definitions, HCPCS look-ups and relevant guideline language in your reference drills.

Pacing the four hours

This is a suggested time budget, not an AAPC timing rule.

Suggested time budget for pacing the four-hour exam
Part of the session	Suggested budget
Average per question	About 1 minute 47 seconds (240 minutes ÷ 135)
Case questions (34)	Budget about 2.5 minutes each, about 85 minutes in total
The other 101 questions	About 1.4 minutes each, about 141 minutes in total
Last 10–15 minutes	Clear your flagged questions and make sure nothing is blank. A blank can't be correct.

Read a case question before its document, so you know what you're looking for. Flag anything that needs a long look-up and come back to it.

Setup checklist

Current AAPC membership, a current email and valid address on file, an unused voucher, and a government photo ID whose name exactly matches your exam confirmation (AAPC prerequisites)
Testing at home: a closed room with window coverings, reliable high-speed internet, a computer, and an external webcam positioned to show your face, hands and keyboard (AAPC at-home exam guidance)
Calculator: the online platform provides one; physical calculators are not allowed. (AAPC exam-day guidance)
Need accommodations? Use AAPC's ADA accommodations process.

Booking walkthrough: AAPC exam registration. After the exam: AAPC exam results.

CPB questions people ask

Is the CPB harder than the CPC? They test different skills. The CPC is 100 coding-heavy questions. The CPB is 135 questions weighted toward insurance, payer policy and cases. (AAPC CPC exam; AAPC CPB exam) If you're choosing between them, compare the two in our medical billing and coding certification guide, or see CPC exam prep.

Do I need billing experience first? AAPC sets no minimum, but it highly recommends two years of experience in the field and warns that its exams aren't meant for people with little or no relevant experience. If you're new, use the 10-week plan to organize your foundations and identify where more training is needed. (AAPC registration prerequisites)

How long should I study? Use the 6-week plan if you've trained or worked in billing, and the 10-week plan if you're newer. Then adjust by your results in each area.

What if I don't pass? AAPC offers one-attempt and two-attempt exam options; check which voucher you purchased. (AAPC exam pricing) For timing and rules, see our AAPC exam retake policy guide.

How do I keep the credential? Keep your annual AAPC membership and earn 36 CEUs every two years if CPB is your only AAPC credential. Multiple credentials have different totals, and the first reporting period may be prorated. (AAPC CEU requirements) Details: AAPC certification renewal.

Sources and independence

Exam facts: AAPC, Certified Professional Biller (CPB) certification; AAPC, Taking the CPB exam; AAPC Support, which years' books to use, book formats, registration prerequisites and ADA accommodations.

Billing rules: CMS, HHS, Medicare.gov, HealthCare.gov, eCFR, CFPB and X12 sources, each linked beside the rule or question it supports.

Last source check: October 21, 2026. This audit checked AAPC's public CPB format, question breakdown, book and registration rules, price and renewal requirements against the linked official sources. It also checked the cited billing-rule passages, independently solved the practice items, and recalculated the amounts and dates. AI assisted with source checking, calculations and targeted corrections. The practice questions, case documents, worked example, review drills and study plans are original Castleport material. Source checking isn't AAPC approval or a credentialed professional review. See our editorial standards.

By the Castleport Test Prep Editorial Team. Castleport Test Prep is an independent exam prep publisher, not affiliated with, endorsed by, or approved by AAPC. Exam and credential names identify their subjects, and trademarks belong to their respective owners. Practice questions are original and unofficial; they aren't AAPC exam questions. This guide doesn't guarantee a passing score, certification, employment or income.