Free ACDIS CCDS Practice Exam with Questions & Answers | Set: 3

When two diagnoses equally meet the definition of principal diagnosis, either condition may be sequenced first when the circumstances of admission, diagnostic workup, and treatment equally support both and no specific coding guideline, tabular instruction, or other sequencing rule directs otherwise.

The principal diagnosis cannot be selected based on which option generates higher payment. Financial outcome is not a legitimate sequencing criterion.

Likewise, chronological age of the diagnosis does not determine principal-diagnosis status. The principal diagnosis is established after study as the condition chiefly responsible for occasioning the admission.

A CDI query may be appropriate when the documentation does not actually establish whether both diagnoses equally occasioned the admission. However, querying simply because one sequencing choice would produce a more favorable MS-DRG is inappropriate.

This scenario tests the distinction between valid coding flexibility and improper reimbursement-driven documentation practices. CDI professionals must understand coding conventions well enough to avoid unnecessary queries while recognizing genuine ambiguity that requires provider clarification.

The FY 2026 MS-DRG grouper and Definitions Manual published by CMS provide the applicable grouper logic for the current fiscal year.

CCDS Reference Topics: Principal diagnosis; equally qualifying diagnoses; sequencing; ethical reimbursement practice.

=========

When an inpatient encounter is solely for administration of chemotherapy, the encounter-for-chemotherapy code is generally sequenced first, followed by the code identifying the malignancy being treated.

This represents an important exception to the usual expectation that the underlying disease is the principal diagnosis. The circumstances of admission are specifically treatment administration rather than management of an acute complication of the malignancy.

If, however, the patient were admitted because of a complication—such as chemotherapy-induced neutropenic fever, dehydration, anemia, or another adverse effect—the principal-diagnosis analysis would follow the applicable guideline for that condition rather than automatically using the chemotherapy encounter code.

Similarly, if chemotherapy were administered incidentally during a hospitalization principally required for another condition, the encounter-for-chemotherapy code would not displace the actual principal diagnosis.

CDI professionals should therefore distinguish planned treatment encounters from admissions caused by complications of treatment or malignancy.

Clear documentation regarding the reason for admission, cancer site, treatment intent, metastatic disease, and complications helps support proper sequencing and accurate oncology data.

CCDS Reference Topics: Antineoplastic chemotherapy; encounter codes; neoplasm sequencing; principal diagnosis; oncology documentation.

=========

The findings strongly support clarification of acute hypercapnic respiratory failure. PaCO₂ of 74 mmHg represents marked carbon dioxide retention, while pH 7.19 demonstrates significant respiratory acidemia. The patient is also hypoxemic and requires urgent noninvasive ventilatory assistance.

Because there is no documented chronic hypercapnic baseline, the available information primarily supports an acute process rather than chronic respiratory failure.

Acute hypercapnia occurs when alveolar ventilation becomes insufficient to eliminate carbon dioxide. Potential causes include COPD or asthma exacerbation, central nervous system depression, neuromuscular weakness, obesity hypoventilation, airway obstruction, or severe fatigue.

BiPAP provides positive-pressure ventilatory support and can improve alveolar ventilation, decrease work of breathing, and lower PaCO₂.

The CDI specialist should not independently establish respiratory failure solely from an ABG. However, the combination of severe physiologic abnormality, respiratory distress, and escalation to BiPAP supplies a strong basis for provider clarification when no corresponding diagnosis is documented.

Metabolic alkalosis would ordinarily involve primary bicarbonate elevation with alkalemia rather than profound respiratory acidemia.

CCDS Reference Topics: Acute respiratory failure; hypercapnia; ABG interpretation; noninvasive ventilation; clinical indicators.

=========

The underlying systemic infection/sepsis code is sequenced as the principal diagnosis when sepsis or severe sepsis is present on admission and is the condition chiefly responsible for admission. Therefore, sepsis is the correct selection from the available choices.

The presence of organ failure means the patient may also meet the documentation requirements for severe sepsis when the acute organ dysfunction is explicitly associated with the sepsis. However, the severe-sepsis code from subcategory R65.2- cannot be assigned as the principal diagnosis. The FY 2026 ICD-10-CM Official Guidelines require the underlying systemic infection first, followed by R65.2- and codes for the associated acute organ dysfunction.

Osteomyelitis represents the localized infection source, but when the reason for admission is sepsis associated with that localized infection, the systemic infection is sequenced first under the sepsis guidelines. “Septicemia” should not be substituted for provider-documented sepsis.

The CDI specialist should also verify that the provider has clearly linked the organ failure to sepsis before severe-sepsis coding is applied.

CCDS Reference Topics: Sepsis sequencing; severe sepsis; principal diagnosis; localized infection.

=========

ICD-10-CM presumes a causal relationship between hypertension and qualifying heart disease, including heart failure, because the conditions are linked under “hypertension, with” in the Alphabetic Index. The presumed relationship applies unless the provider clearly documents that the heart disease is unrelated to hypertension.

Accordingly, hypertensive heart disease is coded using the appropriate I11.- category, with an additional I50.- code identifying the specific type and acuity of heart failure.

This convention differs from conditions for which ICD-10-CM does not provide a presumed causal link. In those circumstances, provider documentation must explicitly establish the relationship.

The CDI specialist therefore should not routinely query merely to obtain wording such as “hypertensive heart failure” when both hypertension and a qualifying heart-failure diagnosis are already documented and no statement says they are unrelated.

However, CDI may still need clarification when heart-failure type or acuity is incomplete, documentation is contradictory, or the physician expressly disputes a hypertensive relationship.

Recognizing these classification-based presumptions reduces unnecessary queries and supports accurate working-code and MS-DRG assignment.

CCDS Reference Topics: Hypertensive heart disease; heart failure; presumed relationships; coding conventions; query necessity.

=========

ICD-10-CM permits a presumed causal relationship between diabetes mellitus and certain conditions indexed under “diabetes, with,” including chronic kidney disease. Therefore, when diabetes and CKD are both documented and the provider has not specifically indicated that they are unrelated, the diabetes-with-CKD combination code is assigned together with an additional code identifying the CKD stage.

For type 2 diabetes, diabetic CKD is classified to E11.22, while an N18.- code identifies the documented CKD stage. In this scenario, stage 4 CKD would be additionally represented by the appropriate stage-specific N18 code.

A query is not routinely necessary simply to obtain wording such as “diabetic CKD” when the classification itself establishes the presumed relationship. However, clarification would be appropriate if documentation explicitly states another unrelated etiology or contains contradictory information.

This distinction is important for CDI because excessive querying can create unnecessary provider burden. CDI specialists must understand which diagnostic relationships require explicit provider linkage and which are established through ICD-10-CM conventions.

The FY 2026 Official Guidelines remain applicable to discharges through September 30, 2026.

CCDS Reference Topics: Diabetes; CKD; presumed causal relationships; combination codes; coding conventions.

=========

When a pressure ulcer progresses to a higher stage during an inpatient stay, ICD-10-CM instructs reporting that preserves both its stage at admission and the highest stage reached during hospitalization.

Therefore, the stage 3 condition present at admission and subsequent progression to stage 4 must both be represented according to the applicable coding instructions.

This approach accurately portrays both the patient's baseline condition and deterioration after admission. Reporting only stage 4 would lose important POA information, while reporting only stage 3 would fail to capture the subsequent clinical severity.

An unstageable pressure-ulcer code is not appropriate simply because the wound changed stages. “Unstageable” has a specific clinical meaning—typically the true depth cannot be determined because the wound base is obscured by slough or eschar or another specified circumstance.

CDI review should ensure documentation includes wound location, stage, laterality when applicable, timing of progression, and relevant wound-care assessment. Qualified wound clinicians may provide pressure-ulcer staging information under applicable non-provider documentation rules.

CCDS Reference Topics: Pressure ulcers; progression; POA; wound staging; quality reporting.

=========

Sepsis resulting from a postprocedural infection follows specialized sequencing rules. The code identifying the postprocedural infection or surgical-site infection is sequenced first when applicable, followed by the code for sepsis following a procedure and any additional codes required for the infectious organism or severe sepsis.

The FY 2026 Official Guidelines specifically state that for sepsis following a postprocedural wound or surgical-site infection, the appropriate postprocedural infection code is sequenced first. An additional code for sepsis following a procedure is then assigned. If severe sepsis exists, the appropriate R65.2- code and codes for acute organ dysfunction are additionally reported.

This differs from ordinary sepsis due to a localized infection, where the systemic infection is typically sequenced before the localized infection when sepsis is the reason for admission.

The cause-and-effect relationship is also essential. A wound infection merely occurring after surgery does not automatically establish a postprocedural complication. Here, the surgeon has explicitly documented that relationship, so the necessary clinical linkage is present.

CCDS Reference Topics: Postprocedural infection; sepsis; surgical-site infection; complication coding; sequencing.

=========

A condition can be assigned present-on-admission status even when the definitive diagnosis is not made until later in the hospitalization. POA refers to whether the condition was present at the time the order for inpatient admission occurred, not the calendar date on which diagnostic confirmation became available.

This distinction is particularly relevant for infections, malignancies, fractures, acute vascular events, and other conditions whose definitive identification may require cultures, pathology, imaging, or additional diagnostic testing.

Therefore, a blood culture finalized on hospital day 3 does not automatically make the infection hospital acquired. The clinical record and provider documentation must establish whether the disease process was present at admission.

POA assignment applies to applicable principal and secondary diagnoses, not only the principal diagnosis. CDI specialists should recognize unclear timing as a potential clarification opportunity because POA status can affect CMS Hospital-Acquired Condition payment logic and quality reporting.

The CCDS content outline expressly includes the basics of POA assignment and its impact on payment, as well as identification of CMS HACs.

CCDS Reference Topics: Present on admission; diagnosis timing; HACs; inpatient coding; quality reporting.

=========

When severe sepsis is documented, coding requires the underlying systemic infection first, followed by the appropriate severe-sepsis code and additional code(s) for the acute organ dysfunction. Therefore, the sepsis code is sequenced first, followed by the severe-sepsis code and acute kidney injury.

The FY 2026 ICD-10-CM Official Guidelines state that severe sepsis requires at least two codes: one for the underlying systemic infection and another from subcategory R65.2-. Additional codes identify associated acute organ dysfunction. A code from R65.2- cannot serve as the principal diagnosis.

The UTI identifies the localized source but does not replace the systemic infection as principal diagnosis when sepsis is the condition chiefly responsible for admission. Likewise, the AKI is a manifestation of the severe systemic process and is not sequenced before the sepsis in this scenario.

For CDI specialists, the essential documentation element is the relationship between sepsis and the acute organ dysfunction. Organ dysfunction alone does not automatically permit severe-sepsis coding; provider documentation must establish the association when it is not inherent.

CCDS Reference Topics: Sepsis; severe sepsis; organ dysfunction; sequencing; principal diagnosis.

=========