ICD 10 Z Codes and External Causes 2 — Questions and Answers
Question 1: External cause codes in ICD-10-CM are located in which chapter?
- Chapter 18 (Symptoms and Signs)
- Chapter 19 (Injury and Poisoning)
- Chapter 20 (External Causes of Morbidity) (Correct answer)
- Chapter 21 (Factors Influencing Health Status)
Correct answer: Chapter 20 (External Causes of Morbidity)
Chapter 20, coded V00-Y99, covers external causes of morbidity including transport accidents, falls, assaults, and undetermined intent.
Question 2: Which external cause code category describes the activity the patient was engaged in at the time of injury?
- Y93 – Activity codes (Correct answer)
- Y99 – External cause status
- Y92 – Place of occurrence
- Y95 – Nosocomial condition
Correct answer: Y93 – Activity codes
Y93 activity codes specify what the patient was doing when injured, such as swimming, walking, or playing a sport.
Question 3: Which external cause code category identifies the place where an injury occurred?
- Y90 – Evidence of alcohol involvement
- Y92 – Place of occurrence (Correct answer)
- Y93 – Activity codes
- Y99 – External cause status
Correct answer: Y92 – Place of occurrence
Y92 codes capture the specific place of occurrence such as the patient's home, a highway, a school, or a public building.
Question 4: Transport accident external cause codes in ICD-10-CM begin with which letter?
- W
- V (Correct answer)
- X
- Y
Correct answer: V
V00-V99 codes cover transport accidents including motor vehicle crashes, pedestrian injuries, and other vehicle-related incidents.
Question 5: External cause codes should be sequenced as:
- The principal diagnosis when the cause is clearly documented
- Secondary codes — they are never sequenced as the principal diagnosis (Correct answer)
- Only for accidental injuries, not assaults or self-harm
- Mandatory only for inpatient hospital admissions
Correct answer: Secondary codes — they are never sequenced as the principal diagnosis
Per ICD-10-CM guidelines, external cause codes are always supplemental secondary codes and may never be the principal or first-listed diagnosis.
Question 6: Which external cause code category covers accidental falls in ICD-10-CM?
- V codes (V00-V99)
- W codes (W00-W19) (Correct answer)
- X codes (X00-X58)
- Y codes (Y10-Y34)
Correct answer: W codes (W00-W19)
W00-W19 codes cover falls including falls on ice, falls from ladders, falls from beds, and other fall scenarios.
Question 7: The external cause status code Y99.8 (Other external cause status) is assigned when the patient:
- Was engaged in an activity of unknown type
- Was participating in leisure or recreational activity
- Was performing work but not military, recreational, or student activity (Correct answer)
- Was injured at a work site with no other details
Correct answer: Was performing work but not military, recreational, or student activity
Y99.8 is a residual status code for activities that do not fit military (Y99.1), leisure (Y99.8 vs Y93), or other defined categories.
ICD 10 Z Codes and External Causes 2
External cause codes in ICD-10-CM are located in which chapter?