CCDS APR-DRG Methodology

Question 1

APR-DRGs differ most fundamentally from MS-DRGs in that APR-DRGs:

Accepted Answer

Assign independent Severity of Illness (SOI) and Risk of Mortality (ROM) subclasses in addition to the base DRG

Answer

APR-DRGs (All Patient Refined DRGs), developed by 3M, layer two additional dimensions — Severity of Illness and Risk of Mortality — each rated on a 1–4 scale. This provides more granular clinical complexity measurement than MS-DRGs, which only differentiate by MCC/CC/no CC.

Question 2

In the APR-DRG system, what is the correct order of Severity of Illness subclasses from least to most severe?

Accepted Answer

Minor, Moderate, Major, Extreme

Answer

APR-DRG SOI subclasses are numbered 1–4 and labeled Minor, Moderate, Major, and Extreme. The same four-level scale applies to the Risk of Mortality subclass. These are the official 3M Health Information Systems designations used in the APR-DRG grouper.

Question 3

Which type of payer most commonly uses APR-DRGs as the basis for hospital reimbursement?

Accepted Answer

Medicaid programs and commercial (non-Medicare) payers in many states

Answer

APR-DRGs were designed to cover all patient types — not just Medicare — and are widely adopted by state Medicaid programs and commercial insurers. Medicare FFS uses MS-DRGs; Critical Access Hospitals use cost-based reimbursement; workers' compensation uses fee schedules.

Question 4

From a CDI perspective, why does accurate secondary diagnosis documentation have an even greater impact in APR-DRGs than in MS-DRGs?

Accepted Answer

APR-DRGs use secondary diagnoses to assign SOI and ROM subclasses, which directly affect the payment weight for each case

Answer

In APR-DRGs, each secondary diagnosis is evaluated for its contribution to SOI and ROM subclass assignment. A single well-documented comorbidity can elevate a case from SOI 2 (Moderate) to SOI 3 (Major), substantially changing expected resource use and reimbursement — an effect more granular than MS-DRG's binary MCC/CC distinction.

Question 5

A hospital uses APR-DRG Risk of Mortality (ROM) subclasses primarily for which of the following purposes?

Accepted Answer

Benchmarking observed versus expected mortality rates for quality reporting and risk adjustment

Answer

The ROM subclass predicts the likelihood that a patient will die during the hospitalization. Hospitals use it to risk-adjust mortality statistics — comparing observed deaths to the number expected given the patient population's ROM distribution — which is central to quality benchmarking and public reporting.

CCDS - Certified Clinical Documentation Specialist Practice Test

CCDS - Certified Clinical Documentation Specialist Practice Test

CCDS APR-DRG Methodology