Free COC Practice Test: 50 Questions With Answers

This free COC practice test has 50 original, unofficial questions for AAPC's Certified Outpatient Coder (COC) exam, spread across AAPC's 10 exam domains in roughly the same proportions as the real 100-question test. Pick an answer, then open the explanation — no signup.

Question 1. A Medicare patient is prepped and taken to the operating room for a hospital outpatient knee arthroscopy planned under general anesthesia. Before induction, the patient develops atrial fibrillation and the surgeon cancels the case. Which modifier belongs on the hospital's claim line for the arthroscopy?

A. 73
B. 53
C. 52
D. 74

Show answer and explanation

Answer: A. 73. Modifier 73 is the facility modifier for a procedure discontinued after the patient was prepared and taken to the procedure room, but before anesthesia was administered. Medicare pays the hospital a reduced (generally 50%) OPPS amount for it.

B (53) is the physician's discontinued-procedure modifier. On the hospital claim, Medicare uses 73 and 74 for procedures where anesthesia is planned or provided.
C (52) is the facility choice only when anesthesia was not planned for the procedure.
D (74) applies after anesthesia has been administered or the procedure has started. Neither happened here.

Source: CMS Medicare Claims Processing Manual, Chapter 4, §20.6.4.

More surgery and modifiers (Questions 2–11)

Question 2. During a Medicare patient's hospital outpatient laparoscopic cholecystectomy, general anesthesia is induced. Before the first incision, the patient becomes hemodynamically unstable and the surgeon stops. Which facility modifier applies?

A. 73
B. 59
C. 52
D. 74

Show answer and explanation

Answer: D. 74. Modifier 74 reports a facility procedure discontinued after anesthesia was administered or after the procedure began. Induction already happened, so 74 applies even though no incision was made. The hospital may receive the full OPPS payment for the discontinued procedure.

A (73) is for cancellations after prep but before anesthesia.
B (59) identifies a distinct procedural service. It says nothing about a discontinued procedure.
C (52) is for reduced or discontinued services where anesthesia was not planned.

Source: CMS Medicare Claims Processing Manual, Chapter 4, §20.6.4.

Question 3. In the hospital radiology department, a Medicare patient is prepared and positioned for a diagnostic imaging procedure that does not require anesthesia. The patient cannot tolerate positioning and the study is stopped before completion. No more limited HCPCS/CPT code accurately describes the completed service. Which modifier should the hospital append?

A. 74
B. 73
C. 52
D. 53

Show answer and explanation

Answer: C. 52. For a reduced radiology study, first use a code that describes the extent actually completed. When no such code exists, the hospital appends 52 to the intended procedure; Medicare applies a 50% payment reduction for the discontinued procedure here.

A and B (74, 73) are only for procedures where anesthesia is planned or provided. CMS specifically says discontinued radiology procedures that don't require anesthesia are not reported with 73 or 74.
D (53) is a physician modifier, not the hospital's choice here.

Source: CMS Medicare Claims Processing Manual, Chapter 4, §§20.6.4 and 20.6.6.

Question 4. A patient is seen in a hospital's outpatient dermatology clinic in the morning. That evening, the same patient is seen in the same hospital's emergency department for an unrelated injury. Both encounters are billed with E/M codes on the hospital's outpatient claim for that date. Which modifier identifies the second E/M encounter as separate and distinct?

A. 25
B. 76
C. 59
D. 27

Show answer and explanation

Answer: D. 27. Modifier 27 is the hospital outpatient modifier for multiple outpatient hospital E/M encounters on the same date. It goes on the second and any later E/M code.

A (25) marks a significant, separately identifiable E/M service on the same day as a procedure. There is no procedure here; there are two visits.
B (76) reports a repeat procedure, not a second visit.
C (59) should not be appended to E/M services.

Source: First Coast Medicare, Modifier 27 fact sheet; CMS MLN1783722, E/M modifier guidance.

Question 5. In a hospital emergency department, a physician repairs a Medicare patient's forehead laceration. During the same visit, the physician also performs a full, separately documented evaluation of new-onset chest pain. The hospital record also supports significant, separately identifiable ED evaluation and management resources for the chest pain, beyond those needed for the repair. On the hospital claim, how should the ED E/M be distinguished from the laceration repair?

A. Append modifier 59 to the E/M code
B. Append modifier XU to the E/M code
C. Append modifier 25 to the E/M code
D. Append modifier 59 to the repair code

Show answer and explanation

Answer: C. Modifier 25 on the E/M code. When a significant, separately identifiable E/M service is provided on the same day as a procedure, modifier 25 goes on the E/M.

A and B fail because modifier 59 — and the X modifiers that refine it — are not appended to E/M services. CMS says to use 25 instead.
D puts a modifier on the wrong line and uses one meant for distinct procedures, not E/M services.

Source: CMS Medicare Claims Processing Manual, Chapter 4, §160; CMS MLN1783722, p. 3, modifier 25 guidance.

Question 6. During one hospital outpatient colonoscopy for a Medicare patient, the gastroenterologist removes a polyp in the sigmoid colon with a snare and, separately, takes a cold-forceps biopsy of a different lesion in the ascending colon. Which code set is correct for the facility?

A. 45385, 45380-XS
B. 45378, 45380, 45385
C. 45385 only
D. 45380, 45385-73

Show answer and explanation

Answer: A. 45385 and 45380-XS. Snare removal and biopsy may both be reported when they are performed on separate lesions. The NCCI edit between them can be bypassed with modifier 59 or XS, and CMS asks for the more specific X modifier whenever one fits. XS means a separate structure — here, a different lesion.

B adds the diagnostic colonoscopy (45378), which is included in any surgical colonoscopy, and has no modifier to bypass the edit.
C loses the biopsy of a separate lesion.
D misuses 73, which is for a discontinued procedure.

Source: Medicare NCCI Policy Manual 2026, Chapter VI, §§C.1 and H.25; CMS MLN1783722.

Question 7. A surgeon performs a punch biopsy of a pigmented lesion on a patient's back, then excises that same lesion during the same session. The biopsy is submitted for pathology, but no result is available before the excision. How is the biopsy reported?

A. Report the biopsy and the excision; append 59 to the biopsy
B. Report the biopsy and the excision; append XS to the biopsy
C. Report the biopsy only
D. Report the excision only

Show answer and explanation

Answer: D. Report the excision only. The lesion-removal code includes the biopsy here. A biopsy of a different lesion may be reported separately. A same-lesion diagnostic biopsy may also be separately reportable when its pathology result determines the decision to proceed immediately with the more extensive procedure; that exception does not apply here.

A and B use a modifier to unbundle a biopsy that is part of the excision. The documentation here does not support a separately reportable diagnostic biopsy.
C drops the definitive procedure.

Source: Medicare NCCI Policy Manual 2026, Chapter I, §A, p. I-5; Medicare NCCI Policy Manual 2026, Chapter III, §E.2.

Question 8. A benign lesion of the arm is excised (excised diameter 1.5 cm). Which closure statement is correct?

A. A simple closure is included in the excision; a layered (intermediate) closure may be reported separately if documented.
B. A simple, single-layer closure is reported separately with a simple repair code.
C. No repair of any type can ever be reported with a benign lesion excision.
D. An intermediate closure is included in the excision; only complex repair is separate.

Show answer and explanation

Answer: A. Simple repair is integral to lesion removal. Intermediate or complex repair may be reported separately when it is medically necessary and documented. One exception to remember: for benign excisions with an excised diameter of 0.5 cm or less, no simple, intermediate or complex repair is reported separately — and this lesion is 1.5 cm.

B unbundles simple closure.
C overstates the 0.5 cm rule, which applies only to very small benign excisions.
D gets the line wrong; intermediate repair is separately reportable.

Source: Medicare NCCI Policy Manual 2026, Chapter III, §E.6.

Question 9. To complete a layered closure of a traumatic laceration, the ED physician trims a small amount of non-viable tissue from the wound edges. How is the trimming reported?

A. It is not reported separately; it is part of the repair
B. With a separate debridement code and modifier 59
C. With a separate debridement code
D. With an active wound care code

Show answer and explanation

Answer: A. Debridement of non-viable tissue that is needed to complete a repair is included in the repair. Depending on documentation, wound-edge debridement can affect the level of repair chosen, but it isn't a separate line.

B, C and D all unbundle work the repair already includes. A modifier doesn't change that.

Source: Medicare NCCI Policy Manual 2026, Chapter III, §E.7; ACEP, Wound Repair FAQ, Q5.

Question 10. A patient has a simple, single-layer repair of a 3.0 cm laceration of the right leg and an intermediate, layered repair of a 2.0 cm laceration of the left arm. How should the repairs be reported?

A. Add the lengths (5.0 cm) and report one intermediate repair code
B. Report the intermediate repair (2.0 cm) and the simple repair (3.0 cm) separately, listing the intermediate repair first
C. Add the lengths (5.0 cm) and report one simple repair code
D. Report only the intermediate repair

Show answer and explanation

Answer: B. Wound lengths are added together only when the repairs share the same classification (simple, intermediate or complex) and the same anatomic grouping. Repairs of different classifications are reported separately, with the more complex repair listed first.

A and C add lengths across different repair classifications.
D drops a documented, separately reportable repair.

Source: ACEP, Wound Repair FAQ, Q10, updated February 2026; WPS LCD L35498, Documentation Requirements.

Question 11. At a separate encounter later on the same day, the same physician repeats an identical diagnostic radiology procedure in the hospital outpatient department because of a change in the patient's condition. Which modifier identifies the repeat on the hospital's claim?

A. 78
B. 77
C. 76
D. 79

Show answer and explanation

Answer: C. 76 — repeat procedure or service by the same physician or other qualified health care professional.

A (78) is an unplanned return to the operating or procedure room for a related procedure during the postoperative period.
B (77) is a repeat by a different physician.
D (79) is an unrelated procedure during the postoperative period.

Source: CMS Medicare Claims Processing Manual, Chapter 4, §20.6.5; Noridian Medicare, Modifier 76 and Modifier 77.

ICD-10-CM (Questions 12–19)

Question 12. In the hospital outpatient clinic, the provider documents: "Cough and fever for 3 days. Probable pneumonia. Chest X-ray ordered." No X-ray result is available. What should be coded?

A. Pneumonia
B. Pneumonia, cough and fever
C. Cough and fever
D. Encounter for screening

Show answer and explanation

Answer: C. Cough and fever (for example, R05.9 and R50.9). In outpatient coding, diagnoses documented as "probable," "suspected," "questionable," "rule out" and similar terms are not coded. Code to the highest degree of certainty for the encounter — here, the symptoms.

A and B code an uncertain diagnosis, which is an inpatient convention, not an outpatient one.
D is wrong because the patient has symptoms; this is not a screening.

Source: ICD-10-CM Official Guidelines, FY 2027, §IV.H, p. 114; official Tabular List and Alphabetic Index, R05.9 and R50.9.

Question 13. A patient is referred to the hospital for an outpatient chest X-ray because of cough. The radiologist's final, signed report is available at the time of coding and documents a definitive diagnosis of pneumonia. What is coded?

A. Cough only
B. Pneumonia and cough
C. Pneumonia only
D. Encounter for routine radiologic examination

Show answer and explanation

Answer: C. Pneumonia only. For an outpatient diagnostic test interpreted by a provider, when the final report is available at the time of coding, code the confirmed diagnosis documented in the interpretation. Don't add related signs and symptoms.

A ignores the confirmed diagnosis.
B adds a symptom that is integral to the confirmed condition.
D is for routine testing with no signs, symptoms or diagnosis.

Source: ICD-10-CM Official Guidelines, FY 2027, §IV.K, pp. 114–115, and §I.B.5, p. 13.

Question 14. A patient has outpatient surgery for a "breast mass." The surgeon's signed postoperative diagnosis, based on the pathology report and available at the time of coding, confirms a fibroadenoma. Which diagnosis is reported for the surgery?

A. Fibroadenoma (benign neoplasm of breast)
B. Breast mass, because it was the preoperative diagnosis
C. Both breast mass and fibroadenoma
D. Abnormal findings on diagnostic imaging of breast

Show answer and explanation

Answer: A. For ambulatory surgery, code the diagnosis the surgery was performed for. If the postoperative diagnosis is known, differs from the preoperative diagnosis and is confirmed, code the postoperative diagnosis.

B uses the less specific preoperative diagnosis even though a confirmed diagnosis is available.
C adds a symptom-level description of the same condition.
D is an imaging-finding code, which doesn't describe a confirmed pathologic diagnosis.

Source: ICD-10-CM Official Guidelines, FY 2027, §IV.N, p. 115.

Question 15. The provider documents hypertension and chronic kidney disease stage 3a, without stating any relationship between them. Which codes are correct?

A. I12.9, N18.31
B. I10, N18.31
C. N18.31, I10
D. I12.0, N18.31

Show answer and explanation

Answer: A. I12.9, N18.31. ICD-10-CM presumes a cause-and-effect relationship between hypertension and CKD, so the combination category I12 is used even without a documented link — unless the provider says the CKD is not due to hypertension. I12.9 covers stage 1–4 or unspecified CKD; N18.31 adds the stage.

B and C report hypertension as unrelated, which the classification doesn't allow without documentation that they are unrelated.
D (I12.0) is for hypertensive CKD with stage 5 or end-stage renal disease.

Source: ICD-10-CM Official Guidelines, FY 2027, §I.C.9.a.2, p. 50, and §I.A.15; official Tabular List and Alphabetic Index, I12 and N18.

Question 16. A patient whose closed fracture was reduced and casted in the emergency department returns two weeks later for a routine cast check. Healing is routine. Which 7th character applies to the fracture code?

A. A
B. G
C. D
D. S

Show answer and explanation

Answer: C. D — subsequent encounter for fracture with routine healing. "D" is used after the patient has completed active treatment and is receiving routine care during the healing or recovery phase, such as cast changes and follow-up visits.

A is for active treatment.
B is for a subsequent encounter with delayed healing.
D (S) is for a sequela — a late effect.

Source: ICD-10-CM Official Guidelines, FY 2027, §§I.C.19.a and I.C.19.c.1, pp. 77–80; official Tabular List and Alphabetic Index, fracture seventh-character definitions, including S52.

Question 17. The provider documents "diabetes mellitus, on long-term insulin, no complications" without stating the type. Which codes apply?

A. E10.9
B. E11.9
C. E13.9, Z79.4
D. E11.9, Z79.4

Show answer and explanation

Answer: D. E11.9, Z79.4. When the type isn't documented, the default is type 2 (E11.-). Insulin use doesn't make it type 1. Add Z79.4 for long-term (current) insulin use.

A assumes type 1 because of insulin.
B omits the insulin-use code.
C (E13) is "other specified" diabetes, which needs documentation of that type.

Source: ICD-10-CM Official Guidelines, FY 2027, §I.C.4.a.2–3, p. 40; official Tabular List and Alphabetic Index, E10.9, E11.9, E13.9 and Z79.4.

Question 18. A patient comes to the hospital's infusion center solely to receive antineoplastic chemotherapy for breast cancer. Which is the first-listed diagnosis?

A. Z51.11, Encounter for antineoplastic chemotherapy
B. The breast cancer code
C. Z51.0, Encounter for antineoplastic radiation therapy
D. Personal history of malignant neoplasm of breast

Show answer and explanation

Answer: A. Z51.11. When an encounter is chiefly for chemotherapy, the Z51.11 code is listed first and the malignancy is listed second.

B is the second code, not the first.
C is for radiation therapy.
D is for a malignancy that has been removed or eradicated, with no evidence of remaining malignancy and no further treatment directed at the site — this patient is under active treatment.

Source: ICD-10-CM Official Guidelines, FY 2027, §IV.L and §§I.C.2.d, I.C.2.e.2 and I.C.2.m; official Tabular List and Alphabetic Index, Z51.11 and Z51.0.

Question 19. A patient with age-related nuclear cataracts in both eyes had the right eye operated on last month; the right-eye cataract no longer exists. Today the patient has cataract surgery on the left eye. Which diagnosis applies today?

A. Bilateral age-related nuclear cataract
B. Age-related nuclear cataract, left eye
C. Age-related nuclear cataract, unspecified eye
D. Age-related nuclear cataract, right eye

Show answer and explanation

Answer: B. Left eye (H25.12). When a bilateral condition is treated in separate encounters, the first encounter uses the bilateral code. At the second encounter, the treated side no longer has the condition, so assign the unilateral code for the remaining side.

A was correct last month, not today.
C discards documented laterality.
D codes a condition that has been treated and no longer exists.

Source: ICD-10-CM Official Guidelines, FY 2027, §I.B.13, p. 15; official Tabular List and Alphabetic Index, H25.12.

Payment methodologies (Questions 20–26)

Question 20. Under the hospital Outpatient Prospective Payment System (OPPS), what does status indicator C mean?

A. Packaged into the payment for other services
B. Paid under a fee schedule other than OPPS
C. Clinic or emergency department visit
D. Inpatient-only procedure; generally not paid under OPPS

Show answer and explanation

Answer: D. Status indicator C identifies procedures on Medicare's inpatient-only (IPO) list. They aren't paid as routine outpatient procedures under OPPS. CMS permits a single claim payment when the patient dies before admission or transfer and the inpatient-only procedure is reported with modifier CA.

A describes status indicator N.
B describes status indicator A.
C describes a visit category, not an inpatient-only procedure.

Source: CMS Transmittal R13573CP, revised Chapter 4 §180.7, pp. 18–19, effective January 1, 2026; CMS Medicare Claims Processing Manual, Chapter 4, §10.1.1 (A and N).

Question 21. A supply on a Medicare hospital outpatient claim carries OPPS status indicator N. How is it paid?

A. A separate APC payment
B. A fee-schedule payment
C. Paid at reasonable cost
D. No separate payment; its payment is packaged into the APC payment for other services

Show answer and explanation

Answer: D. Status indicator N means items and services packaged into APC rates. The item should still be coded and charged according to the applicable reporting instructions — it contributes to cost data — but it doesn't generate its own payment.

A, B and C describe separately payable methods, which N is not.

Source: CMS Medicare Claims Processing Manual, Chapter 4, §§10.1.1 and 10.4.A–C.

Question 22. An Original Medicare hospital outpatient OPPS claim includes a primary procedure with status indicator J1. What does that mean for most of the other covered services on the same claim?

A. Each is paid separately under its own APC
B. They are denied as unbundled
C. They are packaged into a single comprehensive APC payment, with limited exceptions
D. They are paid under the physician fee schedule

Show answer and explanation

Answer: C. J1 means hospital Part B services paid through a comprehensive APC. The comprehensive APC makes one payment for the primary service and packages most other covered services on the claim, except for categories CMS specifically excludes.

A describes ordinary separately payable APCs.
B confuses packaging (paid within the comprehensive APC) with denial.
D does not describe J1: it denotes comprehensive APC payment, not payment under the physician fee schedule.

Source: CMS Medicare Claims Processing Manual, Chapter 4, §§10.2.3 and 10.4.C.6.

Question 23. A hospital outpatient claim has two procedures, both with status indicator T, during the same operative session. The standard OPPS multiple-procedure reduction applies, with no other payment adjustment. Procedure 1's APC payment rate is $1,000; procedure 2's is $600. Ignoring wage adjustment and coinsurance, what is the OPPS payment basis?

A. $1,600
B. $1,300
C. $800
D. $1,000

Show answer and explanation

Answer: B. $1,300. Status indicator T means the multiple procedure reduction applies. The highest-paying procedure is paid at 100% and the other at 50%: $1,000 + ($600 × 0.50) = $1,300.

A ignores the reduction.
C discounts both procedures.
D treats the second procedure as packaged.

Source: CMS Medicare Claims Processing Manual, Chapter 4, §§10.1.1 and 10.5. Calculation from the stated rates.

Question 24. On a Medicare hospital outpatient claim, a code with status indicator Q1 is billed on the same claim as a procedure with status indicator T. How is the Q1 code handled?

A. Paid separately at 50%
B. Paid under the clinical laboratory fee schedule
C. Denied as an inpatient-only service
D. Packaged into the payment for the T procedure

Show answer and explanation

Answer: D. Q1 means "STV-packaged": the code's payment is packaged when it appears on the same claim as a service with status indicator S, T or V. When none of those are on the claim, a Q1 code can be paid separately.

A confuses Q1 packaging with the T multiple procedure reduction.
B describes a fee-schedule service.
C describes status indicator C.

Source: CMS Medicare Claims Processing Manual, Chapter 4, §§10.4.C.2 and 10.4.1; CMS Transmittal R3685CP, claim-level packaging effective January 1, 2017.

Question 25. A Medicare patient has an outpatient visit in a hospital-based clinic. Under OPPS, which code reports the hospital's facility visit?

A. 99213
B. G0121
C. 99283
D. G0463

Show answer and explanation

Answer: D. G0463, the hospital outpatient clinic visit code. Since January 1, 2014, CMS has recognized G0463 for OPPS payment of clinic visits, and the CPT office/outpatient E/M codes are not recognized for OPPS payment.

A (99213) is a CPT office/outpatient E/M code the hospital doesn't use for Medicare OPPS clinic visits.
B (G0121) is a screening colonoscopy code.
C (99283) is an emergency department visit code, not a clinic visit.

Source: CMS Transmittal R2845CP, January 2014 clinic-visit policy; CMS October 2026 HCPCS file, G0463 and G0121.

Question 26. What does OPPS status indicator E1 mean?

A. Packaged service
B. Emergency department visit
C. Items, codes and services not paid by Medicare when submitted on outpatient claims
D. Paid through a comprehensive APC

Show answer and explanation

Answer: C. E1 identifies items, codes and services not paid by Medicare when submitted on outpatient claims.

A is status indicator N.
B is not the meaning of E1; E1 does not identify an emergency department visit category.
D is status indicator J1.

Source: CMS Transmittal R13978CP: October 2026 OPPS update, §5, p. 4, effective October 1, 2026.

CPT coding rules (Questions 27–32)

Question 27. Which statement about CPT add-on codes is correct?

A. They can be reported when no applicable primary service was performed.
B. They can only be reported in addition to a primary procedure.
C. They always require modifier 51.
D. They are reported only by facilities.

Show answer and explanation

Answer: B. An add-on code describes a service that can only be reported in addition to a primary procedure. Add-on codes are exempt from the multiple procedure modifier 51.

A removes the required primary service.
C is backwards.
D is false; physicians and facilities both report them.

Source: Medicare NCCI Policy Manual 2026, Chapter I, §§R and W; Noridian Medicare, Modifier 51, Incorrect Use.

Question 28. The laboratory performs every test in a defined organ or disease panel and one additional test that isn't part of that panel. How is it reported?

A. Each test individually
B. The panel code plus the additional test
C. The panel code only
D. The additional test only

Show answer and explanation

Answer: B. When every test in a defined panel is performed, report the panel code. A test performed in addition to the panel's components is reported separately.

A unbundles the panel.
C drops a separately performed test.
D drops the panel.

Source: Medicare NCCI Policy Manual 2026, Chapter I, §N; Medicare NCCI Policy Manual 2026, Chapter X, §C; CMS Claims Processing Manual, Chapter 16, §90.2.

Question 29. A CPT code is designated "separate procedure." When may it be reported with another procedure on the same date?

A. Only when it is performed independently of, or unrelated to, the other procedure (for example, an anatomically unrelated site or a separate encounter), using an appropriate modifier when required
B. Never, under any circumstances
C. Always, as long as both are documented
D. Only when it is the most expensive procedure

Show answer and explanation

Answer: A. A "separate procedure" is usually a component of a larger related procedure and may not be reported separately with it. It can be reported when it's carried out independently or is unrelated — at a separate encounter, or in an anatomically unrelated area at the same encounter — using an appropriate modifier when required.

B ignores legitimate independent use.
C ignores the bundling rule.
D has nothing to do with the designation.

Source: Medicare NCCI Policy Manual 2026, Chapter I, §J.

Question 30. When should an unlisted procedure code be used?

A. Whenever the payer's fee for the specific code is low
B. Only when no code accurately describes the service performed
C. Instead of a Category III code that describes the service
D. When the procedure was discontinued

Show answer and explanation

Answer: B. An unlisted code is for a service that no existing code accurately describes. When a currently effective Category I code — or a currently effective Category III code — describes the service, report that code instead.

A is a payment motive, not a coding rule.
C reverses the order: an applicable Category III code takes priority over an unlisted code.
D is not a reason by itself to use an unlisted code; follow the applicable discontinued-procedure coding instructions.

Source: Medicare NCCI Policy Manual 2026, Chapter I, §T; AMA, CPT Category III code instructions, pp. 1–2; CMS Medicare Claims Processing Manual, Chapter 4, §20.6.6.

Question 31. A diagnostic colonoscopy turns therapeutic when the physician removes a polyp by snare. Which colonoscopy codes are reported?

A. 45385 only
B. 45378 and 45385
C. 45378 only
D. 45378 with modifier 52 and 45385

Show answer and explanation

Answer: A. 45385 only. A surgical endoscopy includes the diagnostic endoscopy, so the diagnostic colonoscopy code isn't reported with the therapeutic one for the same session.

B and D report the diagnostic endoscopy that is included in 45385.
C drops the procedure that was actually performed.

Source: Medicare NCCI Policy Manual 2026, Chapter VI, §C.1; Massachusetts 2026 ASC code table, pp. 96–97, codes 45378 and 45385.

Question 32. At a hospital outpatient imaging center, a Medicare patient has a bilateral digital screening mammogram and, in the same session, screening digital breast tomosynthesis. Which CPT codes are reported?

A. 77067 only
B. 77063 only
C. 77066, 77063
D. 77067, 77063

Show answer and explanation

Answer: D. 77067, 77063. Report the bilateral screening mammography code (77067) and the screening tomosynthesis add-on code (77063). CMS's NCCI manual specifically allows 77063 to be reported with 77067.

A drops the tomosynthesis, which is separately described.
B reports an add-on code without its primary procedure.
C pairs the screening add-on with a diagnostic mammography code; this was a screening encounter.

Source: Medicare NCCI Policy Manual 2026, Chapter IX, §C.15; CMS October 2026 RVU file, codes 77063, 77066 and 77067.

HCPCS Level II (Questions 33–36)

Question 33. On an Original Medicare hospital outpatient claim, a separately payable, non-vaccine drug has OPPS status indicator K and a drug-specific HCPCS descriptor of "per 10 mg." The hospital administers 80 mg from a 100 mg single-dose vial and documents that the remaining 20 mg is discarded. How is it reported?

A. Two lines: 8 units without JW or JZ, and 2 units with modifier JW
B. One line: 8 units with modifier JZ
C. One line: 10 units
D. Two lines: 8 units with JW, and 2 units with JZ

Show answer and explanation

Answer: A. Report the administered amount on one line without JW or JZ (80 mg ÷ 10 mg = 8 units) and the discarded amount on a second line with modifier JW (20 mg ÷ 10 mg = 2 units).

B attests that nothing was discarded, which is false.
C hides the discarded amount, which must be reported separately.
D puts JW on the administered amount and uses JZ despite documented discard.

Source: CMS JW and JZ Modifier FAQs, Q7, Q14–15 and Q21. Unit math: 80 ÷ 10 = 8; 20 ÷ 10 = 2.

Question 34. On an Original Medicare hospital outpatient claim, the hospital administers the entire contents of a single-dose vial of a separately payable, non-vaccine drug with a drug-specific HCPCS code and OPPS status indicator K; nothing is discarded. Which modifier is appended to the drug line?

A. JW
B. JW with zero units
C. JZ
D. None, because JW and JZ apply only to multi-dose vials

Show answer and explanation

Answer: C. JZ. JZ attests that no amount of a single-dose container drug was discarded. CMS has required it in that situation since July 1, 2023.

A and B would report discarded drug that doesn't exist.
D is backwards — JW and JZ are not used for multiple-dose containers.

Source: CMS JW and JZ Modifier FAQs, Q5, Q7, Q17 and Q21.

Question 35. A procedure is performed on the patient's left great toe. Which HCPCS Level II modifier identifies the site?

A. T5
B. F5
C. FA
D. TA

Show answer and explanation

Answer: D. TA — left foot, great toe.

A (T5) is the right foot, great toe.
B (F5) is the right hand, thumb.
C (FA) is the left hand, thumb.

Source: CMS October 2026 HCPCS file, modifiers TA, T5, FA and F5.

Question 36. A Medicare patient's screening colonoscopy turns into a polypectomy. Which HCPCS Level II modifier tells Medicare that a colorectal cancer screening test was converted to a diagnostic or therapeutic procedure?

A. 33
B. PT
C. GA
D. GY

Show answer and explanation

Answer: B. PT — colorectal cancer screening test converted to a diagnostic test or other procedure. Medicare instructs reporting the CPT code for the procedure actually performed, in place of the screening code (such as G0121), with PT appended.

A (33) is the CPT preventive-services modifier; Medicare uses PT for this situation.
C (GA) indicates a waiver of liability was issued as required by payer policy for the individual case.
D (GY) indicates a statutorily excluded item or service.

Source: CMS Medicare Claims Processing Manual, Chapter 18, §60.1.1; CMS October 2026 HCPCS file, PT, GA and GY.

Compliance and coding guidelines (Questions 37–39)

Question 37. A hospital expects Original Medicare to deny an outpatient test as not reasonable and necessary under a local coverage policy. The patient wants the test and wants Medicare to issue a payment decision. Which action is correct?

A. Give the patient an Advance Beneficiary Notice (ABN) after the test is performed, and append GY
B. Change the diagnosis code to one that the policy covers
C. Give the patient an ABN before the test is performed, and append GA when a valid ABN is on file
D. Bill the patient without filing a Medicare claim

Show answer and explanation

Answer: C. The ABN (form CMS-R-131) must be delivered before the service, when the provider expects Medicare to deny it as not reasonable and necessary. Modifier GA tells Medicare a valid waiver of liability is on file.

A is too late — an ABN after the service doesn't shift liability — and GY is for statutorily excluded services.
B is false coding.
D skips the claim needed for the Medicare payment decision the patient requested.

Source: CMS ABN Tutorial, April 2026, Requirements and Options 1–2; CMS Claims Processing Manual, Chapter 30, §§50.8 and 50.17.A; CMS October 2026 HCPCS file, GA.

Question 38. What is the difference between a National Coverage Determination (NCD) and a Local Coverage Determination (LCD)?

A. NCDs are issued by Medicare Administrative Contractors; LCDs are issued by CMS.
B. NCDs are issued by CMS and apply nationwide; LCDs are issued by Medicare Administrative Contractors and apply within their jurisdictions.
C. Both apply only to Medicare Advantage plans.
D. LCDs override NCDs when they conflict.

Show answer and explanation

Answer: B. CMS issues NCDs, which apply across the country. Medicare Administrative Contractors (MACs) issue LCDs for their regions, often filling gaps where no NCD exists, and LCDs must be consistent with national policy.

A reverses the issuers.
C is false; both govern Original Medicare coverage.
D is backwards — national policy binds the contractors.

Source: CMS, Medicare Coverage of Items and Services, National Coverage Determinations and Local Coverage Determinations.

Question 39. In the ICD-10-CM Tabular List, an Excludes2 note appears under a code. What does it mean?

A. The excluded condition is not part of the condition represented by the code, but the patient may have both, so both codes may be reported when appropriate.
B. Never report the two codes together.
C. The excluded code must be sequenced first.
D. Query the provider every time.

Show answer and explanation

Answer: A. Excludes2 means "not included here." The patient may have both conditions, and both codes may be reported together when appropriate.

B describes the general Excludes1 rule ("not coded here"), which has an exception for unrelated conditions.
C describes a "code first" sequencing note.
D is unnecessary for an Excludes2 note. Query for an Excludes1 note when it is unclear whether the two conditions are related.

Source: ICD-10-CM Official Guidelines, FY 2027, §I.A.12.a–b, pp. 9–10.

Medical terminology and anatomy (Questions 40–45)

Question 40. Which term describes the surgical creation of an opening from the colon to the surface of the abdomen?

A. Colectomy
B. Colostomy
C. Colotomy
D. Coloscopy

Show answer and explanation

Answer: B. Colostomy. The suffix -ostomy means surgically creating an opening.

A (-ectomy) means surgical removal.
C (-otomy) means cutting into (incision).
D (-scopy) means examining, usually with a scope.

Source: MedlinePlus, Word Parts and What They Mean, Procedures, Diagnosis and Surgery.

Question 41. A physician performs a pericardiocentesis. What was done?

A. Removal of the heart's outer lining
B. A puncture to drain fluid from the sac around the heart
C. Surgical repair of a heart valve
D. A visual examination of the heart's chambers

Show answer and explanation

Answer: B. Peri- means around, cardi/o refers to the heart, and -centesis means a surgical puncture to drain fluid.

A would be a pericardiectomy.
C would use -plasty (surgical repair).
D would use -scopy.

Source: MedlinePlus, Word Parts and What They Mean; MedlinePlus, Pericardiocentesis, definition.

Question 42. An operative report describes an arthrodesis. What procedure is this?

A. Joint replacement
B. Puncture of a joint to remove fluid
C. Visual examination of a joint
D. Surgical fusion of a joint

Show answer and explanation

Answer: D. Arthr/o means joint and -desis means surgically binding together, so arthrodesis permanently fuses the bones of a joint.

A is arthroplasty.
B is arthrocentesis.
C is arthroscopy.

Source: MedlinePlus, Word Parts and What They Mean; Cleveland Clinic, Arthrodesis (Joint Fusion), definition.

Question 43. What is the main function of the gallbladder?

A. It produces bile.
B. It produces insulin.
C. It stores bile made by the liver and releases it during digestion.
D. It filters blood to make urine.

Show answer and explanation

Answer: C. The liver makes bile; the gallbladder stores it and releases it through the common bile duct to help digest fats.

A describes the liver.
B describes the pancreas.
D describes the kidneys.

Source: MedlinePlus, Gallbladder Diseases, Summary; NIDDK, Definition & Facts for Pancreatitis, pancreas functions; NIDDK, Your Kidneys & How They Work, urine formation.

Question 44. Which structure lies deepest?

A. Epidermis
B. Dermis
C. Subcutaneous tissue (hypodermis)
D. Stratum corneum

Show answer and explanation

Answer: C. Subcutaneous tissue. From superficial to deep: epidermis, dermis, subcutaneous tissue (hypodermis). Depth matters for coding — repair and debridement choices depend on which layers are involved.

A and D are superficial; the stratum corneum is the outermost layer of the epidermis.
B lies between the epidermis and the subcutaneous tissue.

Source: NCI SEER, Anatomy of the Skin, epidermis, dermis, underlying subcutaneous tissue and Stratum Corneum.

Question 45. A patient has a torn medial meniscus. In which joint is the meniscus?

A. Knee
B. Hip
C. Shoulder
D. Elbow

Show answer and explanation

Answer: A. Knee. Each knee has two menisci — C-shaped cartilage cushions between the thighbone and shinbone.

B has the acetabular labrum.
C has the labrum (glenoid labrum), not a meniscus.
D has no meniscus.

Source: MedlinePlus, Meniscus tears – aftercare; AAOS, Hip Arthroscopy, Anatomy; AAOS, Shoulder Joint Labral Tear, Anatomy of the Shoulder.

Cases (Questions 46–50)

Use your code books. As on the real exam, choose the option with the complete, correctly sequenced code set. External-cause codes are not requested in these cases.

Question 46. Hospital outpatient endoscopy, Medicare patient, age 66, average risk. Indication: screening colonoscopy. Findings: one 8 mm polyp in the sigmoid colon, removed with a hot snare. Remainder of the exam normal. Pathology pending at the time of coding.

A. G0121; Z12.11
B. 45378, 45385-PT; K63.5
C. 45385; K63.5, Z12.11
D. 45385-PT; Z12.11, K63.5

Show answer and explanation

Answer: D. The screening became a therapeutic colonoscopy, so report the snare polypectomy code (45385) in place of the screening code G0121, with modifier PT for Medicare. The screening encounter code (Z12.11) is listed first because screening was the reason for the encounter; the polyp found during screening (K63.5) is an additional diagnosis.

A reports only the screening code and loses the polypectomy.
B adds the included diagnostic colonoscopy and drops the screening diagnosis.
C omits PT and sequences the finding before the screening reason.

Source: ICD-10-CM Official Guidelines, FY 2027, §I.C.21.c.5, p. 98; official Tabular List and Alphabetic Index, Z12.11 and K63.5; Medicare NCCI Policy Manual 2026, Chapter VI, §§C.1 and H.25; CMS Claims Processing Manual, Chapter 18, §§60.1.1 and 60.2.

Question 47. ASC operative report. Preoperative and postoperative diagnosis: age-related nuclear cataract, right eye. Procedure: phacoemulsification of the cataract with insertion of a posterior chamber intraocular lens, right eye. No complex technique, devices or circumstances documented.

A. 66982-RT; H25.11
B. 66984-RT; H25.11
C. 66984-LT; H25.12
D. 66984-RT; H25.13

Show answer and explanation

Answer: B. 66984-RT; H25.11. Routine extracapsular cataract removal with lens insertion in one stage is 66984. RT identifies the right eye, and H25.11 is age-related nuclear cataract of the right eye.

A (66982) requires documented complexity, which isn't present.
C uses the wrong eye.
D (H25.13) is the bilateral code; only the right eye is documented here.

Source: Massachusetts 2026 ASC code table, p. 138, codes 66982 and 66984; ICD-10-CM Official Guidelines, FY 2027, §I.B.13; official Tabular List and Alphabetic Index, H25.11–H25.13; CMS October 2026 HCPCS file, RT and LT.

Question 48. Hospital outpatient surgery. A 1.0 cm pigmented lesion on the back is excised with 0.3 cm margins on all sides, as measured by the surgeon before excision. The surgeon closes the subcutaneous tissue and skin in layers and documents a final repair length of 2.4 cm. Final signed postoperative diagnosis, incorporating the pathology report: benign compound melanocytic nevus.

A. 11401; D22.5
B. 11402, 12031; D22.5
C. 11403, 12031; D22.5
D. 11402; L98.9

Show answer and explanation

Answer: B. 11402, 12031; D22.5.

Excised diameter: largest lesion diameter plus twice the narrowest margin = 1.0 + (0.3 × 2) = 1.6 cm, which falls in the 1.1–2.0 cm range for benign excision of the trunk (11402). Use the surgeon's measurement before excision, not the pathology specimen size, which can shrink.
Closure: closure of the subcutaneous tissue and skin is an intermediate repair. For this 1.6 cm benign excision, the documented 2.4 cm repair on the trunk is separately reportable with 12031.
Diagnosis: a benign melanocytic nevus of the trunk is D22.5.

Why the others fail:

A measures the lesion alone, without margins, and drops the intermediate repair.
C overstates the excised diameter.
D drops the repair and uses a nonspecific skin-disorder code instead of the confirmed pathology.

Source: WPS LCD L35498, lesion-size definition and Documentation Requirements; Medicare NCCI Policy Manual 2026, Chapter III, §E.6; Massachusetts 2026 ASC code table, pp. 3 and 6, codes 11401–11403 and 12031; ACEP, Wound Repair FAQ, Q1 and Q4; ICD-10-CM Official Guidelines, FY 2027, §IV.N; official Tabular List and Alphabetic Index, D22.5 and L98.9.

Question 49. Emergency department. A patient cut the right forearm (3.0 cm) and right upper arm (2.0 cm) on broken glass. No foreign body is found. Both wounds are closed with simple, single-layer sutures. Initial encounter. The provider identifies the forearm laceration as the more serious injury and the focus of treatment.

A. 12001 ×2; S51.811A, S41.111A
B. 12002; S51.811A, S41.111A
C. 12002; S51.811A
D. 12032; S51.811A, S41.111A

Show answer and explanation

Answer: B. 12002; S51.811A, S41.111A. Both repairs are simple and in the same anatomic grouping (extremities), so add the lengths: 3.0 + 2.0 = 5.0 cm, which falls in the 2.6–7.5 cm range for simple repair (12002). Each laceration has its own diagnosis code, with 7th character A for active treatment. The forearm diagnosis is listed first because it is the more serious injury and the focus of treatment.

A reports each wound separately instead of adding them. It also uses a code limited to 2.5 cm or less for the 3.0 cm forearm wound.
C drops the upper-arm laceration diagnosis.
D reports intermediate repair for single-layer closures.

Source: WPS LCD L35498, Documentation Requirements; Massachusetts 2026 ASC code table, p. 6, codes 12001, 12002 and 12032; ICD-10-CM Official Guidelines, FY 2027, §I.C.19.a–b, pp. 77–78; official Tabular List and Alphabetic Index, S51.811A and S41.111A.

Question 50. Hospital outpatient clinic, Medicare patient. The patient is seen for a preoperative evaluation before a scheduled laparoscopic cholecystectomy for symptomatic gallstones without cholecystitis or obstruction. The exam is unremarkable and the patient is cleared for surgery.

A. G0463; Z01.818, K80.20
B. 99213; K80.20
C. G0463; K80.20, Z01.818
D. G0463; Z01.810

Show answer and explanation

Answer: A. G0463; Z01.818, K80.20. The hospital reports clinic visits for Medicare with G0463. For an encounter only for preoperative evaluation, a code from Z01.81- is listed first, followed by the condition that is the reason for the surgery.

B uses a CPT office visit code that OPPS doesn't recognize for clinic visits and omits the preoperative encounter code.
C reverses the sequence.
D uses the cardiovascular preoperative exam code, which isn't documented, and omits the reason for surgery.

Source: ICD-10-CM Official Guidelines, FY 2027, §IV.M, p. 115; official Tabular List and Alphabetic Index, Z01.818, Z01.810 and K80.20; CMS Transmittal R2845CP; CMS October 2026 HCPCS file, G0463.

Score your set and choose what to review

Count your correct answers in each block. The real exam requires at least 70 correct out of 100, so 35 of these 50 is the same proportion — but a practice score is feedback on these 50 questions, not a prediction of your exam result. The review thresholds below are editorial suggestions, not AAPC requirements or validated readiness measures. A few questions per domain provide limited feedback. AAPC exam structure and passing requirement.

Score review by AAPC exam domain: real exam question counts, questions in this set and when to review first
AAPC exam domain	Questions on the real exam	Questions here	Review first if you missed
Surgery and modifiers	22	Q1–Q11	3 or more
ICD-10-CM	15	Q12–Q19	2 or more
Payment methodologies	13	Q20–Q26	2 or more
CPT	13	Q27–Q32	2 or more
Cases	10	Q46–Q50	2 or more
HCPCS Level II	7	Q33–Q36	1 or more
Medical terminology	7	Q40–Q42	1 or more
Anatomy	7	Q43–Q45	1 or more
Compliance	3	Q37–Q38	1 or more
Coding guidelines	3	Q39	1

What to do with your misses:

Facility modifiers (Q1–Q5). Reread CMS's Chapter 4 modifier sections until 52/73/74 and 25/27 feel automatic.
Payment methodologies (Q20–Q26). Learn status indicators as a system: what is paid separately, what is packaged, and what isn't paid under OPPS at all. Payment methodologies account for 13 exam questions, including topics beyond status indicators.
ICD-10-CM (Q12–Q19). Read Section IV of the Official Guidelines in full — it's about five pages.
Cases (Q46–Q50). If you knew the rules but missed the code, practice looking up full code sets under a timer. Speed with the books is a skill of its own.
Repeat the set in three days. Cover the explanations and retake only the questions you missed.

The set includes hospital outpatient and ASC facility coding, along with terminology and anatomy, and every answer explains why the other choices fail. Keep your CPT, ICD-10-CM and HCPCS Level II books open; the real exam allows about 2.4 minutes per question.

Original, unofficial practice questions — not actual AAPC exam questions. Written for 2026 CPT and HCPCS Level II; every ICD-10-CM code used is the same in the FY 2026 and FY 2027 releases. Payment and modifier rules are Medicare's unless a question says otherwise.

This is a 50-question sample, not a full-length exam or complete coverage of every topic in AAPC's blueprint.

COC exam facts that shape your prep

Format: 100 multiple-choice questions in one sitting, with four hours to finish — about 2.4 minutes per question. AAPC exam format.
Passing: an overall score of 70% or higher, meaning at least 70 questions correct. AAPC tells candidates to answer every question, because a guess beats a blank. AAPC passing grades and exam-day guidance.
Content: the 10 domains in the table above. AAPC notes that diagnosis questions also appear inside the CPT categories, and that cases test coding medical record documentation with CPT, ICD-10-CM and HCPCS Level II codes. AAPC domain breakdown.
Delivery: online with a live remote proctor, or in person at a testing center. An online calculator is provided in the testing platform; physical calculators are not permitted. AAPC exam-day rules.
Code books: AAPC bases exams on the current calendar year's code sets and updates them each January. You may bring print books from the current year, the previous year, or a mix: AMA's CPT Professional Edition plus ICD-10-CM and HCPCS Level II from any publisher. Older and upcoming-year books aren't allowed, and only one copy of each book is permitted. Instead of print, you can choose current-year eBooks from the exam platform's library, and change that choice up to 48 hours before the exam. (In 2026, exams moved to 2026 HCPCS Level II codes on March 2.) AAPC book-year policy; Examinee Instructions, p. 3.
Results: typically within 7–10 business days in your AAPC account. AAPC results policy.
After passing: if COC is your only AAPC credential, the standard requirement is 36 CEUs every two years and annual AAPC membership. Candidates who pass without enough work experience hold the apprentice designation (COC-A) until they meet AAPC's experience requirements. AAPC CEU requirements; After the COC exam.

Pricing and voucher options change; check AAPC's COC exam page for the current price before you buy.

How this practice test differs from the CPC

The COC tests facility coding: what the hospital or ASC reports, not what the physician bills. That changes several answers you may have learned for the CPC. The hospital uses 73 and 74 where a physician would use 53, reports clinic visits to Medicare with G0463 instead of CPT office visit codes, and receives Medicare OPPS payments through APCs and status indicators. ASCs use a separate Medicare ASC payment system. CMS NCCI manual, Chapter I, pp. I-1–I-4; CMS hospital payment rules, Chapter 4. Studying for both? Our free CPC practice test covers the professional side.

Useful next steps

Book your exam: AAPC exam registration
After test day: AAPC exam results and AAPC exam retake policy
Keep your credential: AAPC certification renewal
Comparing credentials: Medical billing and coding certification
Official exam details: AAPC: Taking the COC exam

Sources and verification

By Castleport Test Prep Editorial Team

AI tools assisted with drafting and source checking. The questions and explanations were compared with the specific references linked beside them, and exam facts were checked against AAPC's published pages on October 21, 2026. This source and editorial checking is not a credentialed professional review. Editorial standards.

Exam facts

AAPC, Taking the COC exam — format, passing score, domain breakdown, delivery, materials
AAPC, Certified Outpatient Coder (COC) certification
AAPC, 2026 Official Study Guide COC Certification — sample pages
AAPC Support, How are exam results released?
AAPC Support, Which year's books should I use? and Examinee Instructions — code-book years, print versus platform eBooks
AAPC, CEU requirements and After the COC exam

Coding and payment rules

CDC/NCHS, ICD-10-CM Official Guidelines for Coding and Reporting, FY 2026 and FY 2027
CMS, Medicare Claims Processing Manual, Chapter 4
CMS, Transmittal R442CP: Modifiers 52, 73 and 74
CMS, Transmittal R2845CP: January 2014 OPPS update (G0463)
CMS, CY 2026 OPPS final rule claims accounting and Transmittal R3685CP: claim-level conditional packaging
CMS, MLN1783722: Proper Use of Modifiers 59, XE, XP, XS, and XU
CMS, NCCI Policy Manual 2026: Chapter I, Chapter III, Chapter VI, Chapter IX
CMS, JW and JZ Modifier FAQs
CMS, Medicare Coverage of Items and Services
Noridian Medicare, Modifier 73, Modifier 52, Modifier PT, Modifier 76, Modifier 77 and modifier list
CMS, NCCI Policy Manual 2026, Chapter X and Medicare NCCI Add-on Code Edits
CMS, ABN Tutorial, April 2026 and Claims Processing Manual, Chapter 30, §§50.8 and 50.17
WPS Medicare, LCD L35498: lesion measurement and repair documentation
Massachusetts, ASC service-code table effective May 1, 2026 — code descriptors; local payment rates are not used in these questions
CMS, October 2026 RVU file and October 2026 HCPCS file
CDC/NCHS, FY 2027 Tabular List and Alphabetic Index and complete code descriptions

Terminology and anatomy

MedlinePlus, Appendix A: Word Parts and What They Mean, Gallbladder Diseases, Meniscus tears – aftercare
NCI SEER Training Modules, Anatomy of the Skin
Cleveland Clinic, Arthrodesis (Joint Fusion)

Last verified: October 21, 2026 — AAPC COC exam format, passing requirement, domains, delivery, book rules, results and credential maintenance; the coding, payment and anatomy references linked to the 50 items; and the ICD-10-CM codes used here across the October 2025, April 2026 and October 2026 releases.

Castleport Test Prep is an independent exam prep publisher. It is not affiliated with, endorsed by, or approved by AAPC. COC and other credential names identify the exams they describe; trademarks belong to their respective owners. These practice questions are original and are not actual exam questions. CPT is a registered trademark of the American Medical Association. Completing this practice test does not award any certification.