CAISS EXAM 2026 Updated Version
QUESTIONS AND ANSWERS | Complete
Test Bank with Rationales | Grade A+
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Question 1
The Abbreviated Injury Scale (AIS) was originally developed primarily for which purpose?
A. Predicting hospital length of stay
B. Assessing anatomical injury severity for automotive safety research [CORRECT]
C. Determining medical malpractice liability
D. Calculating insurance premiums only
Correct Answer: B
Rationale: The AIS was originally developed by the Association for the Advancement of
Automotive Medicine (AAAM) in 1969 to assess anatomical injury severity, primarily for
automotive safety research and crash injury analysis. While it has expanded to trauma registry
and clinical applications, its fundamental purpose remains anatomical injury severity scoring.
Options A, C, and D represent secondary or incorrect applications.
Question 2
In the 7-digit AIS code structure (AIS 2005+), what does the sixth digit represent?
A. Body region
B. Specific anatomic structure
C. Level of injury
D. Severity score [CORRECT]
Correct Answer: D
Rationale: The 7-digit AIS code format is: Digit 1 = Body region, Digit 2 = Type of anatomic
structure, Digits 3-4 = Specific anatomic structure, Digit 5 = Level, Digit 6 = Severity (1-6),
Digit 7 = Reserved/modifier. The severity score (1-6) is the sixth digit. This is crucial for ISS
calculation and injury classification.
,Question 3
An AIS severity score of 4 indicates which level of injury?
A. Moderate
B. Serious
C. Severe [CORRECT]
D. Critical
Correct Answer: C
Rationale: AIS severity scale: 1 = Minor, 2 = Moderate, 3 = Serious, 4 = Severe, 5 = Critical, 6 =
Maximal (currently untreatable). Severe injuries (AIS 4) are life-threatening but survivable with
optimal care, often requiring surgical intervention. Examples include flail chest, ruptured spleen
with shock, or severe brain contusion.
Question 4
Which statement accurately describes the "single most severe injury per body region" rule for
ISS calculation?
A. Only one injury should be coded per patient
B. Only the highest severity injury in each body region is used for ISS calculation [CORRECT]
C. All injuries must be averaged within each region
D. Multiple injuries in the same region are summed for ISS
Correct Answer: B
Rationale: For ISS calculation, only the single most severe injury (highest AIS score) from each
of the six body regions is used. However, for trauma registry documentation, ALL injuries should
be coded. This rule prevents inflation of ISS from multiple injuries to the same region. Options
A, C, and D misrepresent the ISS methodology.
Question 5
A patient has bilateral rib fractures (left: AIS 2, right: AIS 3). How should this be coded for ISS
purposes?
A. Code both as separate injuries (ISS would use both)
B. Code as bilateral injury with severity reflecting combined effect, using the higher severity
[CORRECT]
C. Code only the left side
,D. Code as two separate body regions
Correct Answer: B
Rationale: Bilateral injuries to the same structure are coded as a single injury with laterality
specified, using the severity that reflects the combined physiological effect. For ISS, only one
thoracic injury can be used, so the higher severity (AIS 3) would be selected. Coding separately
(A) would violate the single injury per region rule. Options C and D are incorrect coding
practices.
Question 6
What is the maximum possible Injury Severity Score (ISS)?
A. 25
B. 50
C. 75 [CORRECT]
D. 100
Correct Answer: C
Rationale: The maximum ISS is 75, calculated as the sum of squares of three AIS 5 injuries (5² +
5² + 5² = 25 + 25 + 25 = 75). If any injury is AIS 6 (maximal), ISS is automatically 75 by
convention. Options A, B, and D are mathematically incorrect based on the ISS formula.
Question 7
Which AIS severity level indicates an injury that is "currently untreatable and invariably fatal"?
A. AIS 4
B. AIS 5
C. AIS 6 [CORRECT]
D. AIS 3
Correct Answer: C
Rationale: AIS 6 (Maximal) indicates injuries that are currently untreatable and invariably fatal,
such as massive brain stem disruption, high cervical cord transection with complete quadriplegia,
or massive liver avulsion. These represent the most severe injuries possible. AIS 5 (Critical) is
survivable with optimal care; AIS 4 (Severe) and AIS 3 (Serious) have progressively better
prognoses.
Question 8
, In AIS coding, what is the correct approach for "unspecified" injuries when more specific
information becomes available?
A. Keep the original unspecified code for consistency
B. Update the code to reflect the most specific information available [CORRECT]
C. Create a new code and keep both
D. Unspecified injuries cannot be changed
Correct Answer: B
Rationale: Trauma registry data quality requires updating codes when more specific diagnostic
information becomes available (e.g., CT scan results, operative findings). The most accurate and
specific AIS code should always be used. Options A, C, and D represent poor data quality
practices.
Question 9
The AIS 2025 update includes which significant change from AIS 2015?
A. Complete elimination of the 7-digit code structure
B. Updated terminology and expanded codes for traumatic brain injury and vascular injuries
[CORRECT]
C. Removal of severity scores 1 and 2
D. Change to a 10-digit coding system
Correct Answer: B
Rationale: AIS 2025 (and recent updates) includes refined terminology for traumatic brain injury
(better correlation with modern imaging), expanded vascular injury codes, and updates to reflect
current clinical practice. The fundamental 7-digit structure (A, D) and severity scale (C) remain
unchanged.
Question 10
When coding penetrating trauma versus blunt trauma, which consideration is most important?
A. Penetrating trauma always receives higher severity scores
B. The mechanism does not affect AIS coding; anatomy and physiology determine severity
[CORRECT]
C. Blunt trauma is always more severe
D. Penetrating trauma cannot be coded with AIS
QUESTIONS AND ANSWERS | Complete
Test Bank with Rationales | Grade A+
Assured | Pass Guaranteed - A+ Graded
Question 1
The Abbreviated Injury Scale (AIS) was originally developed primarily for which purpose?
A. Predicting hospital length of stay
B. Assessing anatomical injury severity for automotive safety research [CORRECT]
C. Determining medical malpractice liability
D. Calculating insurance premiums only
Correct Answer: B
Rationale: The AIS was originally developed by the Association for the Advancement of
Automotive Medicine (AAAM) in 1969 to assess anatomical injury severity, primarily for
automotive safety research and crash injury analysis. While it has expanded to trauma registry
and clinical applications, its fundamental purpose remains anatomical injury severity scoring.
Options A, C, and D represent secondary or incorrect applications.
Question 2
In the 7-digit AIS code structure (AIS 2005+), what does the sixth digit represent?
A. Body region
B. Specific anatomic structure
C. Level of injury
D. Severity score [CORRECT]
Correct Answer: D
Rationale: The 7-digit AIS code format is: Digit 1 = Body region, Digit 2 = Type of anatomic
structure, Digits 3-4 = Specific anatomic structure, Digit 5 = Level, Digit 6 = Severity (1-6),
Digit 7 = Reserved/modifier. The severity score (1-6) is the sixth digit. This is crucial for ISS
calculation and injury classification.
,Question 3
An AIS severity score of 4 indicates which level of injury?
A. Moderate
B. Serious
C. Severe [CORRECT]
D. Critical
Correct Answer: C
Rationale: AIS severity scale: 1 = Minor, 2 = Moderate, 3 = Serious, 4 = Severe, 5 = Critical, 6 =
Maximal (currently untreatable). Severe injuries (AIS 4) are life-threatening but survivable with
optimal care, often requiring surgical intervention. Examples include flail chest, ruptured spleen
with shock, or severe brain contusion.
Question 4
Which statement accurately describes the "single most severe injury per body region" rule for
ISS calculation?
A. Only one injury should be coded per patient
B. Only the highest severity injury in each body region is used for ISS calculation [CORRECT]
C. All injuries must be averaged within each region
D. Multiple injuries in the same region are summed for ISS
Correct Answer: B
Rationale: For ISS calculation, only the single most severe injury (highest AIS score) from each
of the six body regions is used. However, for trauma registry documentation, ALL injuries should
be coded. This rule prevents inflation of ISS from multiple injuries to the same region. Options
A, C, and D misrepresent the ISS methodology.
Question 5
A patient has bilateral rib fractures (left: AIS 2, right: AIS 3). How should this be coded for ISS
purposes?
A. Code both as separate injuries (ISS would use both)
B. Code as bilateral injury with severity reflecting combined effect, using the higher severity
[CORRECT]
C. Code only the left side
,D. Code as two separate body regions
Correct Answer: B
Rationale: Bilateral injuries to the same structure are coded as a single injury with laterality
specified, using the severity that reflects the combined physiological effect. For ISS, only one
thoracic injury can be used, so the higher severity (AIS 3) would be selected. Coding separately
(A) would violate the single injury per region rule. Options C and D are incorrect coding
practices.
Question 6
What is the maximum possible Injury Severity Score (ISS)?
A. 25
B. 50
C. 75 [CORRECT]
D. 100
Correct Answer: C
Rationale: The maximum ISS is 75, calculated as the sum of squares of three AIS 5 injuries (5² +
5² + 5² = 25 + 25 + 25 = 75). If any injury is AIS 6 (maximal), ISS is automatically 75 by
convention. Options A, B, and D are mathematically incorrect based on the ISS formula.
Question 7
Which AIS severity level indicates an injury that is "currently untreatable and invariably fatal"?
A. AIS 4
B. AIS 5
C. AIS 6 [CORRECT]
D. AIS 3
Correct Answer: C
Rationale: AIS 6 (Maximal) indicates injuries that are currently untreatable and invariably fatal,
such as massive brain stem disruption, high cervical cord transection with complete quadriplegia,
or massive liver avulsion. These represent the most severe injuries possible. AIS 5 (Critical) is
survivable with optimal care; AIS 4 (Severe) and AIS 3 (Serious) have progressively better
prognoses.
Question 8
, In AIS coding, what is the correct approach for "unspecified" injuries when more specific
information becomes available?
A. Keep the original unspecified code for consistency
B. Update the code to reflect the most specific information available [CORRECT]
C. Create a new code and keep both
D. Unspecified injuries cannot be changed
Correct Answer: B
Rationale: Trauma registry data quality requires updating codes when more specific diagnostic
information becomes available (e.g., CT scan results, operative findings). The most accurate and
specific AIS code should always be used. Options A, C, and D represent poor data quality
practices.
Question 9
The AIS 2025 update includes which significant change from AIS 2015?
A. Complete elimination of the 7-digit code structure
B. Updated terminology and expanded codes for traumatic brain injury and vascular injuries
[CORRECT]
C. Removal of severity scores 1 and 2
D. Change to a 10-digit coding system
Correct Answer: B
Rationale: AIS 2025 (and recent updates) includes refined terminology for traumatic brain injury
(better correlation with modern imaging), expanded vascular injury codes, and updates to reflect
current clinical practice. The fundamental 7-digit structure (A, D) and severity scale (C) remain
unchanged.
Question 10
When coding penetrating trauma versus blunt trauma, which consideration is most important?
A. Penetrating trauma always receives higher severity scores
B. The mechanism does not affect AIS coding; anatomy and physiology determine severity
[CORRECT]
C. Blunt trauma is always more severe
D. Penetrating trauma cannot be coded with AIS
