ACDIS CCDS cheat sheet

MS-DRG assignment begins by grouping the principal diagnosis into a major diagnostic category (MDC); the principal procedure and qualifying secondary diagnoses (CC/MCC) then refine the final DRG.

IPPS base operating payment = standardized amount × wage index (applied to the labor-related share) plus the nonlabor portion, then adjusted for IME, DSH/uncompensated care, and outliers.

Two-midnight rule: a Medicare Part A inpatient admission is generally appropriate when the practitioner expects the beneficiary to require hospital care spanning at least two midnights, as documented at the time of admission.

Hospital-Acquired Condition (HAC) program places 1% of base operating DRG payments at risk for hospitals in the worst-performing quartile on risk-adjusted HAC measures.

Hospital Readmissions Reduction Program withholds up to 3% of base operating DRG payments for excess 30-day readmissions for specified conditions.

Hospital Value-Based Purchasing withholds 2% of base operating DRG payments and redistributes the pool based on quality and cost measures.

A secondary diagnosis counts toward severity only if it is not on the CC/MCC exclusion list for that principal diagnosis; CC = comorbidity/complication, MCC = major CC.

Other prospective payment systems: SNF uses PDPM, inpatient rehabilitation uses the IRF PPS with CMGs, and home health uses the HH PPS over 30-day periods.

Interrupted stay policy: readmission to the same hospital within 3 days for the same or a related condition is combined with the original stay for IPPS payment.

Anemia thresholds: hemoglobin <13.0 g/dL in men and <12.0 g/dL in women.

Chronic kidney disease requires eGFR <60 mL/min/1.73 m² or markers of kidney damage persisting at least three months.

Heart failure: BNP <100 pg/mL makes acute heart failure unlikely; values ≥400 pg/mL strongly support decompensation in the appropriate clinical setting.

Sepsis-3: suspected infection plus an acute rise in SOFA score of 2 or more points defines sepsis; septic shock adds vasopressor need and lactate >2 mmol/L despite fluids.

qSOFA bedside screen: respiratory rate ≥22, altered mentation, systolic BP ≤100 mm Hg.

Diabetes diagnosis: A1c ≥6.5%, fasting glucose ≥126 mg/dL, or 2-hour OGTT ≥200 mg/dL; hypoglycemia is generally glucose <70 mg/dL.

COPD is confirmed by a post-bronchodilator FEV1/FVC ratio below 0.70; asthma shows reversible airflow obstruction.

Warfarin therapy targets INR 2.0–3.0 for most indications and 2.5–3.5 for mechanical mitral valves; ACE inhibitors cause dry cough and hyperkalemia; loop diuretics cause hypokalemia.

Opioids cause respiratory depression and miosis; naloxone reverses opioid-induced respiratory depression. Corticosteroids raise glucose and mask infection.

A documented diagnosis must be supported by clinical indicators in the record: vital signs, laboratory values, imaging, physical exam findings, and treatment or monitoring.

Cloned, copy-pasted, or carried-forward text that does not reflect the current encounter cannot establish or support a diagnosis.

Query when documentation is conflicting, ambiguous, incomplete, or lacks clinical support for a reported diagnosis.

Principal diagnosis is the condition established after study to be chiefly responsible for occasioning the admission; it may differ from the admission impression.

History of a condition indicates it is resolved and is not coded as an active problem; 'personal history' Z codes are used instead.

Verbal and telephone orders must be documented at the time and authenticated by the ordering practitioner within the timeframe set by medical staff bylaws.

Late entries must be dated, timed, and signed when made; backdating an entry is never permitted.

Only the treating provider may document diagnoses; CDI and coding staff clarify but never alter or add diagnoses to the record.

Excludes1 note = 'not coded here'; the two codes are mutually exclusive and cannot be reported together. Excludes2 note = 'not included here'; both conditions may be coded if documented.

Sequencing instructions include 'code first', 'use additional code', 'code also', and 'code first, if applicable, code also' - each dictates which code is principal.

Inpatient coding uses the principal diagnosis and requires present-on-admission (POA) reporting; outpatient coding uses the first-listed diagnosis and does not report POA.

In ICD-10-CM, 'with' means 'associated with' and presumes a causal relationship unless the documentation states the conditions are unrelated.

Hypertension with heart disease (I11.-) and hypertension with CKD (I12.-) presume a causal relationship; heart failure with CKD does not.

Sepsis requires an underlying systemic infection code (A41.-); R65.20 (severe sepsis without shock) needs associated organ dysfunction, and R65.21 requires septic shock.

Injury codes require a 7th character: A = initial encounter, D = subsequent encounter, S = sequela.

ICD-10-PCS codes have exactly seven alphanumeric characters drawn from 34 values, excluding the letters I and O, and contain no decimals.

When the record supports a more specific diagnosis than the term documented, query the provider instead of defaulting to an unspecified code.

Medicare Part A covers inpatient hospital and post-acute facility care; Part B covers outpatient, physician, and most observation services.

National Coverage Determinations (NCDs) apply nationwide; Local Coverage Determinations (LCDs) apply within a Medicare Administrative Contractor's jurisdiction.

An Advance Beneficiary Notice (ABN) is issued before a service likely to be denied as not medically necessary, shifting financial liability when the beneficiary accepts.

The Medicare Secondary Payer questionnaire determines whether Medicare pays primary or secondary to group health, liability, or workers' compensation coverage.

Medicare Recovery Audit Contractors (RACs) may review claims up to three years from the date of service plus the current year.

Medicare Advantage plans receive risk-adjusted capitation based on submitted diagnoses mapped to hierarchical condition categories (HCCs); RADV audits validate those diagnoses.

Conditions of Participation require utilization review, discharge planning, and medical staff bylaws that govern documentation and order authentication.

Private payers set their own medical necessity criteria, prior authorization rules, and appeal timelines; contractual terms govern denials and timely filing.

The SNF 3-day inpatient rule and the IRF 60% compliance threshold are payer-specific admission requirements that affect site-of-service decisions.

Every query must cite the clinical indicators from the record (labs, vitals, imaging, treatment) that prompted the question.

A compliant query is non-leading: it does not suggest a specific diagnosis or imply a higher-weighted DRG the provider has not documented.

Offer only clinically supported options, and always include 'other' and 'unable to determine' so the provider is not forced into a choice.

Multiple-choice format is preferred over yes/no for open clinical questions; yes/no is reserved for confirming a specific documented finding.

Open-ended queries are appropriate when the clinical evidence suggests a new diagnosis not yet documented.

Query and response should be retained as part of the permanent health record per organizational policy; verbal queries must be documented the same way.

Escalation follows policy: unresolved queries move from the CDI specialist to the physician advisor, then to the department chair.

Provider education is most effective when concurrent, data-driven, and non-punitive, using specialty-specific scorecards and real de-identified record examples.

Case mix index = sum of DRG relative weights for all discharges ÷ total number of discharges.

Query rate = number of queries sent ÷ number of discharges reviewed (often expressed per 100 discharges).

Query response rate = provider responses ÷ queries sent; agreement rate = responses accepting the query ÷ responses received.

CC/MCC capture rate = discharges with a coded CC/MCC ÷ discharges eligible to have one, tracking documentation completeness.

DRG change rate = records whose DRG changed after query ÷ total records reviewed; it measures concurrent CDI impact.

Benchmark sources include CMS IPPS final rule tables, HCUP and state all-payer databases, and internal historical baselines by service line.

Internal audits should use a statistically valid sample and two independent reviewers to measure inter-rater reliability.

OIG compliance: queries must never be generated solely to raise reimbursement; doing so risks False Claims Act exposure regardless of documentation accuracy.

Severity tracking often uses APR-DRG severity of illness and risk of mortality (four levels each) in parallel with the MS-DRG payment weight.