CCDS ACDIS Certified Clinical Documentation Specialist Free Practice Exam Questions (2026 Updated)

Vascular dementia is the correct answer. CMS MS-DRG logic places qualifying vascular dementia diagnoses from category F01.- within MS-DRG 884, Organic Disturbances and Intellectual Disability. The FY 2026 CMS MS-DRG Definitions Manual specifically lists vascular dementia codes among the principal diagnoses assigned to MS-DRG 884.

MS-DRG assignment depends on the principal diagnosis code, major diagnostic category, procedures when applicable, and other grouper logic. Therefore, clinically related forms of dementia do not necessarily group to the same MS-DRG. Alzheimer's disease is classified primarily as a neurologic degenerative disorder and requires appropriate dementia manifestations where applicable. Alcohol-induced dementia is classified within substance-related mental and behavioral disorders, while Wernicke encephalopathy is associated with thiamine deficiency and follows different classification logic.

For CCDS practice, this question illustrates why documentation of dementia etiology and type matters. Simply documenting “dementia” can produce a less specific code and may affect MS-DRG assignment, risk adjustment, severity representation, and quality data.

The CDI specialist should seek clarification only when the clinical record supports a more specific dementia type.

CCDS Reference Topics: MS-DRG assignment; mental disorders; dementia specificity; IPPS reimbursement.

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The clinical pattern supports consideration of acute tubular necrosis (ATN) as a clarification opportunity. Prolonged hypotension can cause renal ischemia severe enough to injure tubular epithelial cells. A substantial acute creatinine increase and granular or “muddy brown” casts are classic clinical findings associated with ATN.

The provider has already documented acute renal failure, so the purpose of the query would be to clarify the underlying type of acute kidney injury when clinically appropriate—not to create AKI from laboratory data alone.

Stage 5 chronic kidney disease requires evidence of chronic, persistent severe renal dysfunction and cannot be inferred from an acute creatinine rise following hypotension. Nephrotic syndrome is characterized principally by substantial proteinuria, hypoalbuminemia, edema, and other findings not described here. Pyelonephritis would ordinarily require evidence of upper urinary infection.

A CDI specialist should review the complete clinical record, including baseline renal function, hemodynamic course, nephrology notes, urinalysis, fluid management, nephrotoxic exposures, and renal replacement therapy when applicable.

The CCDS competency framework includes renal failure, laboratory interpretation, and recognition of clinically supported opportunities for diagnostic specificity.

CCDS Reference Topics: Acute kidney injury; acute tubular necrosis; renal pathophysiology; clinical indicators; diagnostic specificity.

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The maximum payment reduction under the Hospital Readmissions Reduction Program is 3%. CMS expresses this through a payment adjustment factor ranging from 1.0, indicating no reduction, to 0.97, representing the maximum 3% reduction.

The HRRP links Medicare payment to excess readmission performance for specified clinical populations. CMS applies the resulting adjustment to applicable Medicare fee-for-service base operating DRG payments.

This program should not be confused with other Medicare hospital quality-payment initiatives. The HAC Reduction Program imposes a 1% reduction on hospitals in the worst-performing quartile, while Hospital Value-Based Purchasing uses a 2% reduction-and-redistribution mechanism.

CMS's FY 2026 IPPS final rule also finalized changes to HRRP methodology that begin with the FY 2027 program year, including incorporation of Medicare Advantage data into the six readmission measures and shortening the applicable performance period from three years to two.

For CDI, the central obligation remains ensuring that the clinical record accurately portrays patient severity, conditions treated, discharge circumstances, and comorbid disease burden.

CCDS Reference Topics: HRRP; readmission measures; quality reimbursement; payment adjustments; risk adjustment.

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The principal diagnosis is the condition established after study to be chiefly responsible for occasioning the patient's admission to the hospital for care. This is the UHDDS definition used in the ICD-10-CM Official Guidelines for inpatient principal-diagnosis selection.

“After study” is critical. The diagnosis initially suspected in the emergency department may change after diagnostic testing, consultation, treatment response, surgery, pathology, or other evaluation. The final principal diagnosis therefore may differ from the first diagnosis documented.

Relative weight does not determine principal diagnosis. A hospital cannot select a higher-paying condition merely because it produces a more favorable MS-DRG. Similarly, medication volume is not a principal-diagnosis criterion.

For CDI specialists, principal-diagnosis review requires understanding the circumstances surrounding admission, the diagnostic workup, final provider documentation, sequencing conventions, and any chapter-specific guidelines. When two conditions are documented and it is unclear which chiefly occasioned the admission, a provider query may be warranted.

The CCDS content outline specifically tests the principles and application of principal-diagnosis assignment.

CCDS Reference Topics: Principal diagnosis; UHDDS; inpatient sequencing; working MS-DRG.

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