Certified Professional Coder (CPC) Quiz: Assign Icd10 Diagnosis Codes
20 questions · exam conditions
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Assign Icd10 Diagnosis CodesQuestion 1 of 20

A patient is diagnosed with sepsis due to methicillin-resistant Staphylococcus aureus (MRSA). Which ICD-10-CM code is assigned?

A41.01
A41.11
A41.02
A49.02
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Certified Professional Coder (CPC) Quiz

Certified Professional Coder (CPC) Quiz: Assign Icd10 Diagnosis Codes

Practice Assign Icd10 Diagnosis Codes in Certified Professional Coder (CPC) with focused quiz questions that help you check what you know, review explanations, and build confidence with test-style prompts.

What this quiz covers

This quiz focuses on Assign Icd10 Diagnosis Codes, giving you a quick way to practice the rules, question types, and explanations that matter most for Certified Professional Coder (CPC).

How to use this quiz

Try each quiz question before looking at the correct answer. Use the explanations to review missed ideas, then come back to similar questions until the pattern feels familiar.

All questions

Question 1

A patient is diagnosed with sepsis due to methicillin-resistant Staphylococcus aureus (MRSA). Which ICD-10-CM code is assigned?

  1. A41.01
  2. A41.11
  3. A41.02 (correct answer)
  4. A49.02
Explanation: ICD-10-CM A41.02 covers sepsis due to methicillin-resistant Staphylococcus aureus (MRSA). Code A41.01 covers sepsis due to methicillin-susceptible Staphylococcus aureus (MSSA); A41.11 covers sepsis due to other specified Staphylococcus; A49.02 covers MRSA infection, site not specified — this is a site-unspecified infection code, not a sepsis code. Resistance status (MRSA vs. MSSA) determines the specific code selection.

Question 2

A patient is diagnosed with cellulitis of the left lower leg. Which ICD-10-CM code is assigned?

  1. L03.115
  2. L03.116 (correct answer)
  3. L03.119
  4. L03.90
Explanation: ICD-10-CM L03.116 covers cellulitis of the left lower limb. Code L03.115 covers cellulitis of the right lower limb; L03.119 covers cellulitis of an unspecified lower limb. When laterality is documented, the specific laterality code must be assigned — reporting the unspecified code (L03.119) when the side is documented constitutes incomplete coding.

Question 3

A patient is diagnosed with essential (primary) hypertension. Which ICD-10-CM code is assigned?

  1. I10 (correct answer)
  2. I11.9
  3. I12.9
  4. I15.9
Explanation: ICD-10-CM I10 covers essential (primary) hypertension — hypertension with no identified underlying cause. Code I11.9 covers hypertensive heart disease without heart failure; I12.9 covers hypertensive chronic kidney disease with stage 1-4 or unspecified CKD; I15.9 covers secondary hypertension, unspecified. Essential hypertension has no identified secondary cause and is always reported with I10.

Question 4

A patient is diagnosed with bilateral primary osteoarthritis of both knees. Which ICD-10-CM code is assigned?

  1. M17.0 (correct answer)
  2. M17.11
  3. M17.12
  4. M17.9
Explanation: ICD-10-CM M17.0 covers bilateral primary osteoarthritis of the knee — a single combination code for both knees simultaneously. Code M17.11 covers primary osteoarthritis of the right knee only; M17.12 covers primary osteoarthritis of the left knee only; M17.9 covers osteoarthritis of the knee, unspecified. When bilateral involvement is documented, the bilateral code (M17.0) is always preferred over reporting two unilateral codes.

Question 5

A patient is seen for a follow-up visit after completing treatment for a urinary tract infection. The infection has resolved and no current infection is present. Which ICD-10-CM code is first-listed?

  1. N39.0
  2. Z87.440
  3. Z09 (correct answer)
  4. Z87.39
Explanation: ICD-10-CM Z09 (encounter for follow-up examination after completed treatment for conditions other than malignant neoplasm) is the correct first-listed code when a patient returns for follow-up after a resolved condition with no current disease present. Code N39.0 is the active UTI code and should not be reported when the infection is resolved; Z87.440 and Z87.39 are personal history codes used when the condition is documented as past history — not as the reason for the current follow-up visit.

Question 6

A patient is diagnosed with an acute exacerbation of chronic systolic heart failure. Which ICD-10-CM code is assigned?

  1. I50.20
  2. I50.21
  3. I50.23 (correct answer)
  4. I50.9
Explanation: ICD-10-CM I50.23 covers acute-on-chronic systolic (congestive) heart failure — used when a patient with known chronic systolic heart failure presents with an acute decompensation. Code I50.20 covers unspecified systolic heart failure; I50.21 covers acute systolic heart failure (new onset, no prior chronic HF); I50.9 covers unspecified heart failure. The combination of chronic underlying HF with acute exacerbation requires the acute-on-chronic code (I50.23) rather than the unspecified code.

Question 7

A patient is diagnosed with acute appendicitis with perforation. Which ICD-10-CM code is assigned?

  1. K35.2
  2. K35.21
  3. K37
  4. K35.20 (correct answer)
Explanation: ICD-10-CM K35.20 covers acute appendicitis with perforation and peritonitis, without mention of abscess — the correct code for a straightforward perforated appendicitis without abscess formation. Code K35.2 is the unrevised parent entry, now expanded; K35.21 covers perforated appendicitis with peritonitis and abscess; K37 covers unspecified appendicitis. When perforation is documented without abscess, K35.20 is the specific code required.

Question 8

A patient is diagnosed with atrial fibrillation, chronic (permanent). Which ICD-10-CM code is assigned?

  1. I48.0
  2. I48.11
  3. I48.20
  4. I48.21 (correct answer)
Explanation: ICD-10-CM I48.21 covers permanent atrial fibrillation — defined as chronic AF in which rate control is the treatment goal and rhythm conversion is no longer pursued. Code I48.0 covers paroxysmal atrial fibrillation (episodic, self-terminating); I48.11 covers longstanding persistent AF (continuous for more than 12 months); I48.20 covers chronic atrial fibrillation, unspecified. Permanent AF is clinically and administratively distinct from persistent AF and requires I48.21.

Question 9

A patient is diagnosed with HIV disease presenting with Pneumocystis jirovecii pneumonia (PCP). Which ICD-10-CM code sequence is correct?

  1. B59, B20
  2. B20, B59 (correct answer)
  3. Z21, B59
  4. B20, J18.9
Explanation: Per ICD-10-CM Official Guidelines, when a patient with HIV disease is admitted for an HIV-related condition, B20 (HIV disease) is sequenced first, followed by the code for the HIV-related condition — in this case B59 (Pneumocystosis). Code Z21 is used for asymptomatic HIV infection status, not for a patient with active HIV disease. B59 specifically covers Pneumocystis jirovecii pneumonia and is more specific than J18.9 (unspecified pneumonia).

Question 10

A patient has COPD and is admitted for an acute lower respiratory tract infection. Which ICD-10-CM code is assigned for the COPD component?

  1. J44.1
  2. J44.9
  3. J44.0 (correct answer)
  4. J45.51
Explanation: ICD-10-CM J44.0 covers chronic obstructive pulmonary disease with acute lower respiratory infection. An additional code is required to identify the infection. Code J44.1 covers COPD with acute exacerbation (not infection); J44.9 covers COPD, unspecified — used when no acute complication is documented; J45.51 covers severe persistent asthma with acute exacerbation, which is an asthma code, not a COPD code. The distinction between acute lower respiratory infection (J44.0) and acute exacerbation (J44.1) is clinically significant.

Question 11

A patient is diagnosed with stage 3 chronic kidney disease (CKD) with no hypertension. The provider documents stage 3a specifically. Which ICD-10-CM code is assigned?

  1. N18.30
  2. N18.31 (correct answer)
  3. N18.32
  4. N18.3
Explanation: ICD-10-CM was updated to include N18.31 (CKD stage 3a) and N18.32 (CKD stage 3b) to allow greater specificity within stage 3. Code N18.3 is now the unspecified stage 3 code when substage is not documented; N18.30 is not a valid ICD-10-CM code. When the provider documents stage 3a specifically, N18.31 is required over the unspecified N18.3.

Question 12

A patient is diagnosed with type 1 diabetes mellitus with diabetic peripheral angiopathy without gangrene. Which ICD-10-CM code is assigned?

  1. E10.51 (correct answer)
  2. E10.52
  3. E11.51
  4. E10.59
Explanation: ICD-10-CM E10.51 covers type 1 diabetes mellitus with diabetic peripheral angiopathy without gangrene. Code E10.52 covers type 1 DM with diabetic peripheral angiopathy with gangrene; E11.51 covers type 2 DM with diabetic peripheral angiopathy without gangrene — the same vascular complication but for type 2 diabetes; E10.59 covers type 1 DM with other circulatory complications. Diabetes type (1 vs. 2) is the first axis of specificity in the E10/E11 code families.

Question 13

A patient is diagnosed with major depressive disorder, recurrent, moderate. Which ICD-10-CM code is assigned?

  1. F33.1 (correct answer)
  2. F32.1
  3. F33.0
  4. F32.0
Explanation: ICD-10-CM F33.1 covers major depressive disorder, recurrent, moderate. Code F32.1 covers major depressive disorder, single episode, moderate; F33.0 covers major depressive disorder, recurrent, mild; F32.0 covers major depressive disorder, single episode, mild. Two axes of specificity are required: episode type (single vs. recurrent) and severity (mild, moderate, severe).

Question 14

A patient sustains a grade II ankle sprain of the lateral ligaments of the right ankle, initial encounter. Which ICD-10-CM code is assigned?

  1. S93.401A
  2. S93.402A
  3. S93.409A
  4. S93.411A (correct answer)
Explanation: ICD-10-CM S93.411A covers sprain of the calcaneofibular ligament of the right ankle, initial encounter. For a lateral ankle sprain, the specific ligament involved should be coded when documented. Code S93.401A covers sprain of unspecified ligament of the right ankle; S93.402A covers sprain of unspecified ligament of the left ankle; S93.409A covers sprain of unspecified ligament of an unspecified ankle. When the specific ligament is documented, the more specific code is required over the unspecified ligament code.

Question 15

A patient is seen for an encounter specifically for screening of colorectal cancer. No current symptoms are present. Which ICD-10-CM code is first-listed?

  1. Z80.0
  2. Z85.038
  3. Z12.11 (correct answer)
  4. C18.9
Explanation: ICD-10-CM Z12.11 covers encounter for screening for malignant neoplasm of the colon. Screening codes are reported as the first-listed diagnosis when a patient presents specifically for cancer screening with no symptoms. Code Z80.0 covers a family history of malignant neoplasm of the digestive organs; Z85.038 covers personal history of other malignant neoplasm of the large intestine; C18.9 covers malignant neoplasm of the colon, which is not reported until a malignancy is confirmed.

Question 16

A patient is seen for a vaccination encounter only — the patient is otherwise healthy with no other conditions addressed. Which ICD-10-CM code is first-listed?

  1. Z00.00
  2. Z11.0
  3. Z13.88
  4. Z23 (correct answer)
Explanation: ICD-10-CM Z23 covers encounter for immunization. This is the first-listed diagnosis when the patient's only reason for the visit is to receive a vaccine. Code Z00.00 covers an encounter for general adult examination without abnormal findings; Z11.0 covers encounter for screening for intestinal infectious diseases; Z13.88 covers encounter for screening for disorder due to exposure to contaminants. The procedure code for the vaccine administration is reported separately alongside Z23.

Question 17

A patient is diagnosed with a primary malignant neoplasm of the upper outer quadrant of the right female breast. Which ICD-10-CM code is assigned?

  1. C50.011
  2. C50.211
  3. C50.411 (correct answer)
  4. C50.811
Explanation: ICD-10-CM C50.411 covers malignant neoplasm of the upper outer quadrant of the right female breast. The breast neoplasm code structure identifies morphology type (1=nipple, 2=central, 4=upper outer, 8=overlapping), laterality (1=right, 2=left), and sex (1=female, 2=male). Accurate site and laterality documentation is required for correct code selection.

Question 18

A patient is involved in a motor vehicle accident and sustains injuries. The external cause of the injuries should be reported using which ICD-10-CM chapter?

  1. Chapter 19 (S00-T88)
  2. Chapter 20 (V01-Y99) (correct answer)
  3. Chapter 18 (R00-R99)
  4. Chapter 21 (Z00-Z99)
Explanation: ICD-10-CM Chapter 20 (V01-Y99) covers External Causes of Morbidity, including transport accidents (V codes), falls (W codes), assault (X codes), and other external causes. Chapter 19 (S00-T88) covers the injuries themselves; Chapter 18 (R00-R99) covers symptoms and abnormal findings; Chapter 21 (Z00-Z99) covers factors influencing health status. External cause codes from Chapter 20 are reported as additional codes, not as the principal diagnosis.

Question 19

A patient is diagnosed with deep vein thrombosis (DVT) of the right femoral vein, acute. Which ICD-10-CM code is assigned?

  1. I82.401
  2. I82.4H1
  3. I82.411 (correct answer)
  4. I82.491
Explanation: ICD-10-CM I82.411 covers acute deep vein thrombosis of the right femoral vein. Code I82.401 covers acute DVT of an unspecified deep vein of the right lower extremity; I82.4H1 covers acute DVT of the right peroneal vein; I82.491 covers acute DVT of other specified deep vein of the right lower extremity. Accurate DVT coding requires laterality, the specific vessel, and acuity (acute vs. chronic).

Question 20

A patient is diagnosed with community-acquired pneumonia due to Streptococcus pneumoniae. Which ICD-10-CM code is assigned?

  1. J18.9
  2. J13 (correct answer)
  3. J15.20
  4. J18.1
Explanation: ICD-10-CM J13 covers pneumonia due to Streptococcus pneumoniae. Code J18.9 covers unspecified pneumonia; J15.20 covers pneumonia due to staphylococcus, unspecified; J18.1 covers lobar pneumonia, unspecified organism. When the causative organism is documented, the organism-specific code takes precedence over unspecified pneumonia codes.