ICD-10-CM practice questions
Z00.00 vs Z00.01 Practice Questions
Eight original multiple-choice questions on first-listed diagnosis rules and choosing Z00.00 or Z00.01 for an adult exam, with guideline-cited answers.
Reviewed 2026-10-20 | 8 questions
These questions practice two outpatient rules that often appear together: how the first-listed diagnosis is chosen, and when a routine adult exam is reported with or without abnormal findings. Each answer cites the FY 2027 ICD-10-CM Official Guidelines or Tabular List. The scenarios are short and synthetic; they are written for this page and do not repeat any Etio case.
Question 1
Fill in the blank. In the outpatient setting, the term first-listed diagnosis is used in lieu of ______.
- A. Principal diagnosis
- B. Secondary diagnosis
- C. Admitting diagnosis
- D. Chief complaint
Show answer and explanation
Answer: A. Principal diagnosis
Section IV.A of the outpatient guidelines says first-listed diagnosis is used in lieu of principal diagnosis. The UHDDS definition of principal diagnosis does not apply to hospital-based outpatient services or provider office visits, so outpatient reporting names the first code by its position instead.
Sources: ICD-10-CM Official Guidelines for Coding and Reporting FY 2027, Section IV.A, Selection of first-listed condition
Practice this rule: Medication Adjustment and Risk-Factor Review, Maintenance Inhaler and Chronic Care Review
Question 2
An office note documents three conditions that were addressed at the visit. Which condition is listed first?
- A. The condition with the most serious long-term outlook
- B. The condition shown in the record to be chiefly responsible for the services provided
- C. The condition written first in the problem list
- D. The chronic condition the patient has had the longest
Show answer and explanation
Answer: B. The condition shown in the record to be chiefly responsible for the services provided
Section IV.G directs you to list first the diagnosis, condition, problem, or other reason for the encounter shown in the record to be chiefly responsible for the services provided. Coexisting conditions follow as additional codes. Severity, duration, and the order of a problem list do not decide the first-listed code.
Sources: ICD-10-CM Official Guidelines for Coding and Reporting FY 2027, Section IV.G, ICD-10-CM code for the diagnosis, condition, problem, or other reason for encounter/visit
Practice this rule: Medication Adjustment and Risk-Factor Review, Maintenance Inhaler and Chronic Care Review
Question 3
An adult comes in for a scheduled annual physical with no complaints. The provider reviews the patient's hypothyroidism, documents it as stable on the current dose, and continues the medication. Nothing new is found. Which code set is correct?
- A. Z00.01, E03.9
- B. Z00.00, E03.9
- C. E03.9, Z00.00
- D. E03.9 only
Show answer and explanation
Answer: B. Z00.00, E03.9
An abnormal finding is a newly identified condition or a change in severity of a chronic condition. A stable chronic condition is neither, so the exam is Z00.00. Chronic conditions may be added as additional codes during a routine exam, and Z00 codes may only be reported first, which rules out listing E03.9 ahead of the exam code.
Sources: ICD-10-CM Official Guidelines for Coding and Reporting FY 2027, Section IV.P, Encounters for general medical examinations with abnormal findings; ICD-10-CM Official Guidelines for Coding and Reporting FY 2027, Section I.C.21.c.12, Routine and Administrative Examinations; ICD-10-CM Official Guidelines for Coding and Reporting FY 2027, Section I.C.21.c.15, Z Codes That May Only be Principal/First-Listed Diagnosis
Practice this rule: Routine Adult Health Examination, Routine Thyroid Follow-Up
Question 4
During an annual adult physical, a patient with established essential hypertension has high readings on repeat measurement. The provider documents the hypertension as uncontrolled. No other problems are found. Which code set is correct?
- A. Z00.00, I10
- B. I10, Z00.01
- C. Z00.01, I10
- D. Z00.01, R03.0
Show answer and explanation
Answer: C. Z00.01, I10
Section IV.P names uncontrolled hypertension as an example of a change in severity that makes the exam one with abnormal findings. Z00.01 is first-listed and a secondary code identifies the finding. Uncontrolled hypertension is still coded to categories I10 to I15, and R03.0 is only for an elevated reading without an established diagnosis of hypertension.
Sources: ICD-10-CM Official Guidelines for Coding and Reporting FY 2027, Section IV.P, Encounters for general medical examinations with abnormal findings; ICD-10-CM Official Guidelines for Coding and Reporting FY 2027, Section I.C.9.a.7 and I.C.9.a.9, Hypertension, Transient and Uncontrolled
Practice this rule: Annual Preventive Visit, Medication Adjustment and Risk-Factor Review
Question 5
An adult has a routine physical with no complaints. A lipid panel drawn as part of the exam returns before the encounter is coded, and the provider documents a new diagnosis of hyperlipidemia, unspecified. Which code set is correct?
- A. Z00.00, E78.5
- B. Z00.01, E78.5
- C. E78.5, Z00.00
- D. Z00.00 only
Show answer and explanation
Answer: B. Z00.01, E78.5
Code assignment depends on what is known when the encounter is coded. Here the result is back and the provider has documented a newly identified condition, which is an abnormal finding. Report Z00.01 first and add E78.5, as the Tabular note at Z00.01 instructs. Laboratory examinations associated with the periodic exam are included in Z00.0.
Sources: ICD-10-CM Official Guidelines for Coding and Reporting FY 2027, Section I.C.21.c.12, Routine and Administrative Examinations; ICD-10-CM Official Guidelines for Coding and Reporting FY 2027, Section IV.P, Encounters for general medical examinations with abnormal findings; FY 2027 ICD-10-CM Tabular List and Alphabetic Index, Tabular List, subcategory Z00.0 and code Z00.01
Practice this rule: Annual Preventive Visit, Medication Adjustment and Risk-Factor Review
Question 6
A routine adult exam finds nothing abnormal. Blood work was drawn, but the encounter is coded before the results return. Which first-listed code is acceptable?
- A. Z00.01
- B. Z00.00
- C. Z01.812
- D. Z01.89
Show answer and explanation
Answer: B. Z00.00
The guidelines give this exact situation as an example: when no abnormal findings were found and the encounter is coded before test results are back, the without abnormal findings code is acceptable. Z01.812 is for a preprocedural laboratory examination. Z01.89 is for an encounter for routine laboratory or radiology testing alone, not a general exam.
Sources: ICD-10-CM Official Guidelines for Coding and Reporting FY 2027, Section I.C.21.c.12, Routine and Administrative Examinations; ICD-10-CM Official Guidelines for Coding and Reporting FY 2027, Section IV.K, Patients receiving diagnostic services only
Practice this rule: Routine Adult Health Examination
Question 7
A routine physical identifies a new condition. Which statement about sequencing is correct?
- A. The new condition is listed first and Z00.01 follows it
- B. Z00.01 is listed first and a secondary code identifies the finding
- C. Only the code for the new condition is reported
- D. Z00.00 is listed first because the visit was scheduled as routine
Show answer and explanation
Answer: B. Z00.01 is listed first and a secondary code identifies the finding
When a general medical examination results in an abnormal finding, the with abnormal finding code is assigned as the first-listed diagnosis and a secondary code identifies the finding. Category Z00 is also on the list of Z codes that may only be reported first.
Sources: ICD-10-CM Official Guidelines for Coding and Reporting FY 2027, Section IV.P, Encounters for general medical examinations with abnormal findings; ICD-10-CM Official Guidelines for Coding and Reporting FY 2027, Section I.C.21.c.15, Z Codes That May Only be Principal/First-Listed Diagnosis
Practice this rule: Annual Preventive Visit
Question 8
A patient booked for an annual physical instead spends the visit having new ankle swelling evaluated. No preventive exam is performed, and the provider documents no diagnosis for the swelling. How is the encounter coded?
- A. Z00.00
- B. Z00.01 with a code for the swelling
- C. The code for the sign or symptom, without a Z00.0- code
- D. Z00.00 followed by a code for the swelling
Show answer and explanation
Answer: C. The code for the sign or symptom, without a Z00.0- code
Routine exam codes are not used when the examination is for diagnosis of a suspected condition, and the Tabular List excludes examination of a sign or symptom from Z00.0. With no confirmed diagnosis, the sign or symptom code is the reason for the encounter.
Sources: FY 2027 ICD-10-CM Tabular List and Alphabetic Index, Tabular List, subcategory Z00.0, Excludes1 note; ICD-10-CM Official Guidelines for Coding and Reporting FY 2027, Section I.C.21.c.12, Routine and Administrative Examinations; ICD-10-CM Official Guidelines for Coding and Reporting FY 2027, Section IV.D, Codes that describe symptoms and signs
Practice this rule: Recent Respiratory Symptom Visit, Digestive Symptom Evaluation