CCDS Exam Practice Questions with Answers and Rationales 2026
SECTION 1: Coding and Reimbursement (Questions 1–30)
1. The MS-DRG payment system is primarily based on which of the following?
A. Hospital charges
B. Principal diagnosis, secondary diagnoses, procedures, and discharge disposition
C. Length of stay only
D. Physician fees
Answer: B. MS-DRGs classify inpatient stays based on the principal diagnosis, secondary diagnoses
(including CCs/MCCs), procedures, and discharge disposition. Hospital charges do not determine MS-
DRG assignment.
Rationale: The IPPS payment methodology uses MS-DRGs to group clinically similar patients consuming
similar resources. CCs (complications/comorbidities) and MCCs (major CCs) increase the relative weight
and thus payment.
2. A patient is admitted with sepsis secondary to a urinary tract infection. The provider documents
"urosepsis." What should the CDI specialist do?
A. Code urosepsis as the principal diagnosis
,B. Query the provider because urosepsis is not a codable term
C. Assign sepsis with UTI as the source without query
D. Code only the UTI
Answer: B. "Urosepsis" is not a codable term in ICD-10-CM and has been historically considered
ambiguous. The CDI specialist should query for clarification of whether the provider means sepsis with
UTI as the source, or a urinary tract infection without sepsis.
Rationale: When a provider documents urosepsis and the clinical picture supports sepsis, query for
clarification; do not assume a sepsis code.
3. Which of the following is considered a major complication or comorbidity (MCC) when documented
as a secondary diagnosis?
A. Controlled hypertension
B. Acute respiratory failure
C. Mild anemia
D. Chronic stable angina
Answer: B. Acute respiratory failure (J96.0x) is classified as an MCC in the MS-DRG system. Controlled
hypertension and mild anemia are typically CCs or non-CCs.
Rationale: MCCs significantly increase the severity of illness and the DRG relative weight. Acute
respiratory failure is a high-impact MCC commonly targeted by CDI programs.
4. The principal diagnosis is defined as:
A. The condition that required the most resources
,B. The condition established after study to be chiefly responsible for the admission
C. The first condition documented in the record
D. The most severe condition regardless of admission reason
Answer: B. The principal diagnosis is the condition established after study to be chiefly responsible for
occasioning the admission to the hospital.
Rationale: UHDDS defines the principal diagnosis as that condition established after study to be chiefly
responsible for occasioning the admission of the patient to the hospital for care. It may differ from the
admission diagnosis.
5. What is the primary impact of an MCC on MS-DRG assignment?
A. It reduces the length of stay
B. It moves the DRG to a higher-weighted group
C. It has no impact on payment
D. It changes the principal diagnosis
Answer: B. An MCC as a secondary diagnosis moves the case to a higher-weighted MS-DRG, increasing
reimbursement.
Rationale: CCs and MCCs are central to MS-DRG assignment because they increase the relative weight
and reflect greater resource consumption.
6. Which of the following best describes the "case mix index" (CMI) in the context of CDI?
A. The total number of patients discharged
, B. The average relative weight of all DRGs for a hospital
C. The ratio of nurses to patients
D. The number of queries sent per month
Answer: B. CMI is the average relative weight of all MS-DRGs assigned to a hospital's patients. It reflects
the complexity and severity of the patient population.
Rationale: Case mix index implications are a core CDI content area. A higher CMI generally indicates a
more complex patient mix and higher average reimbursement per case.
7. When a patient has two conditions equally meeting the definition of principal diagnosis, which should
be sequenced first?
A. The one with the higher DRG weight
B. The one documented first in the admission note
C. Either may be sequenced first per coding guidelines
D. The one with the lower severity
Answer: C. When two or more diagnoses equally meet the criteria for principal diagnosis, either may be
sequenced first, according to ICD-10-CM guidelines.
Rationale: The Official Guidelines for Coding and Reporting allow either condition to be sequenced first
when both equally meet the definition of principal diagnosis.
8. A patient is admitted for elective knee replacement and also has poorly controlled diabetes. The
diabetes is documented as "controlled" on admission. How should this affect the DRG?
A. Controlled diabetes is always an MCC
SECTION 1: Coding and Reimbursement (Questions 1–30)
1. The MS-DRG payment system is primarily based on which of the following?
A. Hospital charges
B. Principal diagnosis, secondary diagnoses, procedures, and discharge disposition
C. Length of stay only
D. Physician fees
Answer: B. MS-DRGs classify inpatient stays based on the principal diagnosis, secondary diagnoses
(including CCs/MCCs), procedures, and discharge disposition. Hospital charges do not determine MS-
DRG assignment.
Rationale: The IPPS payment methodology uses MS-DRGs to group clinically similar patients consuming
similar resources. CCs (complications/comorbidities) and MCCs (major CCs) increase the relative weight
and thus payment.
2. A patient is admitted with sepsis secondary to a urinary tract infection. The provider documents
"urosepsis." What should the CDI specialist do?
A. Code urosepsis as the principal diagnosis
,B. Query the provider because urosepsis is not a codable term
C. Assign sepsis with UTI as the source without query
D. Code only the UTI
Answer: B. "Urosepsis" is not a codable term in ICD-10-CM and has been historically considered
ambiguous. The CDI specialist should query for clarification of whether the provider means sepsis with
UTI as the source, or a urinary tract infection without sepsis.
Rationale: When a provider documents urosepsis and the clinical picture supports sepsis, query for
clarification; do not assume a sepsis code.
3. Which of the following is considered a major complication or comorbidity (MCC) when documented
as a secondary diagnosis?
A. Controlled hypertension
B. Acute respiratory failure
C. Mild anemia
D. Chronic stable angina
Answer: B. Acute respiratory failure (J96.0x) is classified as an MCC in the MS-DRG system. Controlled
hypertension and mild anemia are typically CCs or non-CCs.
Rationale: MCCs significantly increase the severity of illness and the DRG relative weight. Acute
respiratory failure is a high-impact MCC commonly targeted by CDI programs.
4. The principal diagnosis is defined as:
A. The condition that required the most resources
,B. The condition established after study to be chiefly responsible for the admission
C. The first condition documented in the record
D. The most severe condition regardless of admission reason
Answer: B. The principal diagnosis is the condition established after study to be chiefly responsible for
occasioning the admission to the hospital.
Rationale: UHDDS defines the principal diagnosis as that condition established after study to be chiefly
responsible for occasioning the admission of the patient to the hospital for care. It may differ from the
admission diagnosis.
5. What is the primary impact of an MCC on MS-DRG assignment?
A. It reduces the length of stay
B. It moves the DRG to a higher-weighted group
C. It has no impact on payment
D. It changes the principal diagnosis
Answer: B. An MCC as a secondary diagnosis moves the case to a higher-weighted MS-DRG, increasing
reimbursement.
Rationale: CCs and MCCs are central to MS-DRG assignment because they increase the relative weight
and reflect greater resource consumption.
6. Which of the following best describes the "case mix index" (CMI) in the context of CDI?
A. The total number of patients discharged
, B. The average relative weight of all DRGs for a hospital
C. The ratio of nurses to patients
D. The number of queries sent per month
Answer: B. CMI is the average relative weight of all MS-DRGs assigned to a hospital's patients. It reflects
the complexity and severity of the patient population.
Rationale: Case mix index implications are a core CDI content area. A higher CMI generally indicates a
more complex patient mix and higher average reimbursement per case.
7. When a patient has two conditions equally meeting the definition of principal diagnosis, which should
be sequenced first?
A. The one with the higher DRG weight
B. The one documented first in the admission note
C. Either may be sequenced first per coding guidelines
D. The one with the lower severity
Answer: C. When two or more diagnoses equally meet the criteria for principal diagnosis, either may be
sequenced first, according to ICD-10-CM guidelines.
Rationale: The Official Guidelines for Coding and Reporting allow either condition to be sequenced first
when both equally meet the definition of principal diagnosis.
8. A patient is admitted for elective knee replacement and also has poorly controlled diabetes. The
diabetes is documented as "controlled" on admission. How should this affect the DRG?
A. Controlled diabetes is always an MCC
