Certified Professional Coder (CPC) Quiz: Apply Diagnosis Sequencing Rules
20 questions · exam conditions
0:00
Apply Diagnosis Sequencing RulesQuestion 1 of 20

A patient is admitted to the hospital with fever, cough, and shortness of breath. After workup, the physician documents a final diagnosis of community-acquired pneumonia due to Streptococcus pneumoniae. Which diagnosis is reported as the principal diagnosis?

Fever
Shortness of breath
Cough
Pneumonia due to Streptococcus pneumoniae (J13)
← Back to quizzes

Certified Professional Coder (CPC) Quiz

Certified Professional Coder (CPC) Quiz: Apply Diagnosis Sequencing Rules

Practice Apply Diagnosis Sequencing Rules 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 Apply Diagnosis Sequencing Rules, 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 admitted to the hospital with fever, cough, and shortness of breath. After workup, the physician documents a final diagnosis of community-acquired pneumonia due to Streptococcus pneumoniae. Which diagnosis is reported as the principal diagnosis?

  1. Fever
  2. Shortness of breath
  3. Cough
  4. Pneumonia due to Streptococcus pneumoniae (J13) (correct answer)
Explanation: For inpatient coding, the principal diagnosis is the condition established after study to be chiefly responsible for the admission. Once a definitive diagnosis is established, signs and symptoms (fever, cough, shortness of breath) that are integral to the condition are not reported separately. J13 is the correct and only principal diagnosis.

Question 2

A patient is admitted for chemotherapy for primary malignant neoplasm of the breast. The patient receives the chemotherapy without complication. Which diagnosis is sequenced as the principal diagnosis?

  1. The chemotherapy encounter code (Z51.11) (correct answer)
  2. The primary malignant neoplasm of the breast
  3. The adverse effect of the chemotherapy drug
  4. The patient's most severe comorbidity
Explanation: Per ICD-10-CM Official Guidelines, when a patient is admitted solely to receive chemotherapy, the encounter for antineoplastic chemotherapy (Z51.11) is sequenced as the principal diagnosis. The malignancy being treated is then reported as a secondary diagnosis. This is an exception to the general rule of sequencing the underlying condition as principal.

Question 3

A patient is admitted for a postoperative wound infection following an appendectomy performed two weeks earlier. Which condition is sequenced as the principal diagnosis?

  1. The original appendicitis diagnosis
  2. The appendectomy procedure code
  3. The postoperative wound infection (correct answer)
  4. The status post appendectomy Z code
Explanation: The postoperative wound infection is the condition responsible for the current admission and is sequenced as the principal diagnosis. A complication code (T81.49XA — infection following a procedure) may be used. The original appendicitis and the prior appendectomy are historical information and may be captured by the complication code as secondary context.

Question 4

A pregnant patient at 32 weeks gestation is admitted for acute appendicitis and undergoes an appendectomy. Which condition is sequenced as the principal diagnosis?

  1. Acute appendicitis
  2. The obstetric complicating condition code from Chapter 15 (correct answer)
  3. Status of pregnancy at 32 weeks
  4. The surgical procedure code
Explanation: ICD-10-CM Official Guidelines state that when a pregnant patient has a condition that occurs during pregnancy, a code from Chapter 15 (O00-O9A) is used as the principal diagnosis to reflect the obstetric context, followed by the applicable code for the complicating condition. Obstetric codes take sequencing priority during pregnancy.

Question 5

A patient is seen in the outpatient clinic for a pre-operative physical examination before an elective knee replacement. The physician finds no new problems. Which is the correct first-listed diagnosis?

  1. Osteoarthritis of the knee (the reason for the upcoming surgery)
  2. Pre-operative examination (Z01.818) (correct answer)
  3. Status post previous knee surgery
  4. Encounter for pre-procedural cardiovascular examination (Z01.810)
Explanation: For a pre-operative examination in the outpatient setting, the appropriate Z code is sequenced as the first-listed diagnosis. Z01.810 is specifically limited to the pre-procedural cardiovascular examination. Z01.818 covers all other pre-procedural examinations — including orthopedic pre-operative evaluations — and is the correct code for this encounter. The condition necessitating the upcoming surgery (osteoarthritis of the knee) is reported as a secondary diagnosis.

Question 6

Two conditions that meet the definition of principal diagnosis are both present at discharge and either could have been selected. The ICD-10-CM Official Guidelines address this situation. What is the correct action?

  1. The attending physician must designate the principal diagnosis
  2. The condition with the higher-valued DRG is selected as principal
  3. The more chronic of the two conditions is selected as principal
  4. Either condition may be sequenced as the principal diagnosis (correct answer)
Explanation: The ICD-10-CM Official Guidelines state that when two or more interrelated conditions each meet the definition of principal diagnosis and are equally responsible for occasioning the admission, either may be sequenced first. The coder may use clinical judgment and available documentation but is not required to seek physician clarification in this specific circumstance.

Question 7

A neonate is born in the hospital and is found to have a congenital heart defect. The physician documents the defect as the only condition affecting the newborn. Which ICD-10-CM chapter provides the principal diagnosis code for this birth encounter?

  1. Chapter 15 — Pregnancy, Childbirth, and Puerperium
  2. Chapter 16 — Certain Conditions Originating in the Perinatal Period
  3. Chapter 17 — Congenital Malformations, Deformations, and Chromosomal Abnormalities (correct answer)
  4. Chapter 21 — Factors Influencing Health Status
Explanation: For newborn records when a congenital anomaly is documented as the primary condition, a code from Chapter 17 (Q00-Q99, Congenital Malformations, Deformations, and Chromosomal Abnormalities) is used. Chapter 16 codes (P00-P96) apply to conditions originating in the perinatal period, not congenital structural anomalies. The birth status code (Z38.xx) is also reported for the birth encounter.

Question 8

A patient is admitted for dehydration secondary to acute gastroenteritis. The gastroenteritis resolves, but the dehydration continues to require IV fluid therapy. Which condition is the principal diagnosis at discharge?

  1. Acute gastroenteritis
  2. Dehydration (correct answer)
  3. Both are equally principal; either may be listed first
  4. The IV fluid administration code
Explanation: The principal diagnosis is determined after study as the condition chiefly responsible for the admission. The gastroenteritis resolved while the dehydration persisted and required ongoing IV fluid treatment. Dehydration is therefore the condition that remained the focus of care and is sequenced as the principal diagnosis. If both conditions were still active and equal at discharge, either could be listed first.

Question 9

A patient with type 2 diabetes is admitted for diabetic chronic kidney disease, stage 3. The ICD-10-CM Tabular List shows an instructional note under the diabetes code stating "Use additional code to identify stage of CKD." How are these conditions sequenced?

  1. CKD stage 3 (N18.3) first, then diabetes with CKD (E11.22)
  2. Diabetes with CKD (E11.22) first, then CKD stage 3 (N18.3) (correct answer)
  3. Either order is acceptable since both conditions are equally relevant
  4. Only one code is needed if a combination code exists
Explanation: ICD-10-CM combination code E11.22 covers type 2 diabetes mellitus with diabetic chronic kidney disease. E11.22 is sequenced first as the principal or first-listed diagnosis, with N18.3 (CKD, stage 3) reported as an additional code per the Tabular List instruction "Use additional code to identify stage of CKD." The use additional code instruction always follows the primary code. E11.65 covers type 2 DM with hyperglycemia and does not capture the diabetes-CKD relationship.

Question 10

A coder encounters the ICD-10-CM instructional note "Use additional code, if applicable, to identify." What does this instruction require?

  1. The additional code is reported only when the condition or factor is present and documented (correct answer)
  2. The additional code must always be reported, regardless of documentation
  3. The additional code is optional and at the coder's discretion
  4. The coder should substitute the additional code for the primary code
Explanation: The instruction "Use additional code, if applicable" means the secondary code is reported only when the stated condition is present and documented in the medical record. It is not a mandatory requirement unless the condition exists. This contrasts with "Code first" instructions, which are mandatory sequencing requirements when both conditions are present.

Question 11

A patient receives outpatient radiation therapy for primary lung cancer. Which is the correct first-listed diagnosis for this encounter?

  1. Primary malignant neoplasm of the lung
  2. Signs and symptoms of lung cancer
  3. Secondary malignant neoplasm
  4. Encounter for radiation therapy (Z51.0) (correct answer)
Explanation: Per ICD-10-CM Official Guidelines, when a patient is admitted or seen for the sole purpose of receiving radiation therapy, Z51.0 (encounter for antineoplastic radiation therapy) is sequenced as the first-listed diagnosis. The malignancy being treated is reported as a secondary diagnosis. This is analogous to the chemotherapy encounter sequencing rule.

Question 12

A patient undergoes an elective total hip replacement for osteoarthritis of the left hip. The postoperative note documents the procedure as status post left total hip arthroplasty, no complications. For the surgical inpatient admission, which condition is the principal diagnosis?

  1. Status post total hip arthroplasty (Z96.641)
  2. Encounter for orthopedic surgery (Z48.89)
  3. Primary osteoarthritis of the left hip (M16.12) (correct answer)
  4. Acquired absence of the left hip joint
Explanation: The principal diagnosis for a surgical admission is the condition that prompted the need for surgery — the osteoarthritis of the left hip (M16.12). Z96.641 (presence of left artificial hip joint) is a status code reported after surgery to indicate the implanted device. Z48.89 is a follow-up code not appropriate as the principal diagnosis for the surgical encounter itself.

Question 13

An outpatient patient presents with chest pain. After evaluation, the physician's final assessment is "chest pain, rule out myocardial infarction." What is the correct first-listed diagnosis for this outpatient encounter?

  1. Chest pain (correct answer)
  2. Myocardial infarction
  3. Abnormal EKG findings
  4. Rule-out myocardial infarction as a combination code
Explanation: For outpatient coding, "rule out" conditions are not coded as if confirmed. The ICD-10-CM Official Guidelines instruct outpatient coders to report the sign or symptom (chest pain) rather than the unconfirmed condition being ruled out. This differs from inpatient coding, where a rule-out condition may be coded as if established when it is still under investigation at discharge.

Question 14

A patient with a known primary malignant neoplasm of the colon presents with a pathologically confirmed metastasis to the liver. The patient is admitted for treatment of both sites. Which condition is sequenced first?

  1. Secondary malignant neoplasm of the liver
  2. Primary malignant neoplasm of the colon (correct answer)
  3. Either may be sequenced first per coder discretion
  4. A combination code covers both conditions and is listed alone
Explanation: Per ICD-10-CM Official Guidelines, when treatment is directed at both a primary and secondary (metastatic) malignancy, the primary malignancy is sequenced first. The secondary malignancy (metastasis to the liver, C78.7) is reported as an additional diagnosis. If treatment were directed only at the metastasis and the primary was no longer under active treatment, the metastasis would be sequenced first.

Question 15

A patient is admitted with acute systolic heart failure and is also found to have chronic atrial fibrillation and type 2 diabetes, both stable and managed during the admission. Which condition is the principal diagnosis?

  1. Chronic atrial fibrillation
  2. Type 2 diabetes
  3. Acute systolic heart failure (correct answer)
  4. All three conditions are equally principal and may be listed in any order
Explanation: The principal diagnosis is the condition determined after study to be chiefly responsible for the hospital admission. Acute systolic heart failure is the acute condition that necessitated the admission. Chronic atrial fibrillation and type 2 diabetes are comorbidities coded as secondary diagnoses because they were managed but did not drive the admission.

Question 16

A patient is being seen in the outpatient setting for management of essential hypertension and type 2 diabetes without complications. Both conditions are being monitored and managed. Which sequencing guideline applies?

  1. Only the more serious condition is reported
  2. The diabetes is always listed before the hypertension per alphabetical convention
  3. Both conditions are reported; either may be listed first as both are reason for the visit (correct answer)
  4. Only the condition that required the most physician work is reported
Explanation: For outpatient encounters where multiple chronic conditions are being managed, all conditions addressed during the visit are reported. When two equally relevant conditions both represent the reason for the encounter, either may be listed as the first-listed diagnosis. There is no strict alphabetical or severity-based sequencing rule for equally weighted outpatient diagnoses.

Question 17

The ICD-10-CM Tabular List instructs "Code first underlying disease" beneath a manifestation code. Which sequencing rule does this instruction reflect?

  1. The etiology code is sequenced first, followed by the manifestation code (correct answer)
  2. The manifestation code is sequenced first, followed by the etiology
  3. The manifestation code is reported alone without an etiology code
  4. Both codes may be sequenced in any order the coder prefers
Explanation: The etiology/manifestation convention in ICD-10-CM requires that the underlying disease (etiology) be sequenced first, followed by the manifestation code. Manifestation codes (often shown in italics in the Tabular List) cannot be used as principal or first-listed diagnoses. The "Code first" and "Use additional code" instructions enforce this required sequencing.

Question 18

A patient is admitted following a myocardial infarction that occurred 5 weeks ago and is now presenting with ongoing complications. Which ICD-10-CM code category applies?

  1. I21 — Acute myocardial infarction
  2. I22 — Subsequent myocardial infarction
  3. I25 — Chronic ischemic heart disease (correct answer)
  4. I23 — Certain current complications following MI
Explanation: ICD-10-CM category I22 (Subsequent myocardial infarction) applies only when a new MI occurs within 4 weeks of a prior MI. An MI that occurred 5 weeks ago falls outside this window; the appropriate category is I25 (Chronic ischemic heart disease), specifically I25.2 (Old myocardial infarction), used when the patient is no longer receiving active care for the original event. I21 is for an acute MI currently under treatment; I23 is for specific complications arising during the acute phase.

Question 19

A patient is admitted with sepsis due to a urinary tract infection caused by E. coli. Which sequencing is correct?

  1. UTI first, then E. coli, then sepsis
  2. E. coli code first, then sepsis, then UTI
  3. UTI first, then sepsis, then E. coli
  4. Sepsis (A41.51 — E. coli sepsis) first, then the localized infection (UTI, N39.0) (correct answer)
Explanation: Per ICD-10-CM Official Guidelines, when sepsis is present with a localized infection, the sepsis code is sequenced first. A41.51 captures sepsis due to E. coli. N39.0 (UTI) is then reported as the source of the sepsis. The organism is captured within A41.51 itself, so no separate organism code is needed.

Question 20

A patient is admitted for surgical repair of a hip fracture. The fracture occurred as a result of a fall from a ladder at a construction site. How are the fracture and external cause codes sequenced?

  1. External cause code first, followed by the fracture code
  2. Fracture code first, followed by the external cause codes for mechanism, place, and work status (correct answer)
  3. The external cause code is the only code needed when the cause is documented
  4. External cause codes are never reported for injuries requiring surgery
Explanation: The injury code (fracture) is always sequenced as the principal or first-listed diagnosis. External cause codes provide supplemental information and are never sequenced as the principal diagnosis. For this scenario, W11.XXXA (fall on and from ladder, initial encounter) captures the mechanism, Y92.61 (construction area as place of occurrence) captures the location, and Y99.0 (civilian activity done for income or pay) captures the work status. These are all reported as additional codes.