A complete guide to CC and MCC codes in ICD-10-CM. Learn how Complications and Comorbidities vs Major Complications affect MS-DRG assignment and hospital reimbursement.
In ICD-10-CM coding, CC stands for Complication or Comorbidity and MCC stands for Major Complication or Comorbidity. These designations are assigned by CMS to specific diagnosis codes based on their clinical severity and the additional resources they require during a hospital stay.
CC and MCC codes are critical to hospital reimbursement because they directly affect the MS-DRG (Medicare Severity Diagnosis Related Group) assignment — and therefore the amount Medicare pays the hospital for that patient encounter.
Simple rule: MCCs represent the most severe conditions. CCs are significant but less severe. Both increase reimbursement — MCCs more so than CCs.
Most MS-DRGs have three payment levels based on the presence of CCs and MCCs in the claim:
| MS-DRG | Description | Payment Level |
|---|---|---|
| 193 | Pneumonia with MCC | Highest |
| 194 | Pneumonia with CC | Middle |
| 195 | Pneumonia without CC/MCC | Lowest |
When a patient is admitted with pneumonia and also has acute respiratory failure (an MCC), the hospital bills under DRG 193 and receives significantly higher reimbursement than if no CC or MCC was present. The difference can be thousands of dollars per case.
Not all diagnoses qualify as CC or MCC codes. CMS publishes the official CC/MCC list annually as part of the IPPS Final Rule. Here are common examples:
| ICD-10 Code | Description | Designation |
|---|---|---|
| J96.00 | Acute respiratory failure, unspecified | MCC |
| E11.10 | Type 2 diabetes with ketoacidosis | MCC |
| A41.9 | Sepsis, unspecified organism | MCC |
| I50.9 | Heart failure, unspecified | CC |
| N18.4 | Chronic kidney disease, stage 4 | CC |
| E11.65 | Type 2 diabetes with hyperglycemia | CC |
An important rule: a CC or MCC only counts toward DRG assignment if it is a secondary diagnosis. The principal diagnosis — the condition primarily responsible for the admission — cannot be its own CC or MCC. It must be a comorbidity or complication that coexists with the principal diagnosis.
Additionally, not all secondary diagnoses qualify as CCs or MCCs in every case. CMS maintains an exclusion list that prevents certain diagnoses from functioning as CCs or MCCs when paired with specific principal diagnoses, to prevent inappropriate upcoding.
Documentation matters: A CC or MCC code can only be assigned when the physician has clearly documented the condition in the medical record and it meets the UHDDS definition of a reportable diagnosis — meaning it was evaluated, treated, or affected the patient's care during the stay.
Coders often identify clinical indicators in the record that suggest a CC or MCC condition may be present but has not been explicitly documented. In these situations, a clinical documentation integrity (CDI) query is appropriate. Common query opportunities include:
Querying is not upcoding — it is ensuring the coded record accurately reflects the severity of the patient's condition.
CMS updates the CC and MCC designation list annually with each IPPS Final Rule. For FY2026 (effective October 1, 2025), coders should verify current designations using updated references rather than prior year lists, as codes can be added, removed, or reclassified between MCC and CC.
ICD10Source uses the official CMS FY2026 IPPS Final Rule CC/MCC data and flags all 1,404 CC and MCC codes directly in search results.
| Feature | CC | MCC |
|---|---|---|
| Severity level | Significant | Most severe |
| Reimbursement impact | Moderate increase | Largest increase |
| DRG tier | Middle tier | Top tier |
| FY2026 code count | 1,071 codes | 333 codes |
| Must be | Secondary diagnosis | Secondary diagnosis |
| Documentation required | Yes — clinically evaluated | Yes — clinically evaluated |
The information in this guide is based on official U.S. government publications. Always verify coding information against the most current official sources before use in billing or clinical documentation.
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