⚖️ CC/MCC Reference — Complication & Comorbidity Designation Guide

One-Line Definition

A CC (Complication or Comorbidity) or MCC (Major Complication or Comorbidity) is a secondary ICD-10-CM diagnosis that CMS has designated as significantly increasing the resources required to treat a patient, thereby qualifying the case for a higher-weighted MS-DRG tier.

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📌 Why This Note Exists

The CC/MCC list is the single most impactful variable a coder controls in DRG assignment. Everything else — the MDC, the surgical pathway — is largely determined by the principal diagnosis and procedure. But the tier within that DRG (w/ MCC vs w/ CC vs w/o CC/MCC) lives entirely in secondary diagnosis capture.

The Stakes

The reimbursement difference between a No-CC DRG and an MCC DRG for the same base DRG can be $4,000-$15,000+ depending on the hospital’s base rate. Missing a documented, supportable MCC is both a revenue integrity failure and an incomplete representation of patient complexity.

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🗂️ Section Index

1. 🔢 How CC/MCC Designation Works
2. 🚫 The CC Exclusion List
3. 🏥 POA and HAC Interaction
4. 🔴 High-Value MCCs — Universal
5. 🟡 High-Value CCs — Universal
6. 🫘 Urology-Specific CC/MCC Table
7. 👂 ENT/OTO-Specific CC/MCC Table
8. 👁️ Ophthalmology-Specific CC/MCC Table
9. 🦽 PM&R-Specific CC/MCC Table
10. 📋 CC/MCC by Body System — Quick Reference
11. 🛠️ Coder Workflow for CC/MCC Capture

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🔢 How CC/MCC Designation Works

Assignment Logic

1. CMS publishes the designation table annually with each IPPS Final Rule (effective October 1)
2. Every ICD-10-CM code is classified as: MCC / CC / Non-CC
3. The grouper evaluates all coded secondary diagnoses against this list
4. The highest-severity qualifying secondary diagnosis determines the DRG tier
5. If one MCC is present → MCC-tier DRG, regardless of how many CCs are also present
6. If CCs present but no MCC → CC-tier DRG
7. If no qualifying CC or MCC → base (no CC/MCC) DRG

What Makes a Diagnosis “Qualifying”

To count toward CC/MCC status, the secondary diagnosis must:

Requirement	Details
Be separately documented	Cannot be inherent to or part of the principal diagnosis
Pass the CC Exclusion List	Not on the exclusion pairing list for the principal diagnosis
Have a valid POA indicator	POA = Y, W, or 1 — POA = N diagnoses may trigger HAC exclusion
Be clinically significant	Evaluated, treated, or documented as affecting the hospital stay
Meet UHDDS secondary diagnosis criteria	Requires evaluation, treatment, therapeutic intervention, or increased nursing care

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🚫 The CC Exclusion List

CMS maintains a CC Exclusion List that pairs principal diagnoses with secondary diagnoses that are too closely related (integral to, manifestation of, or non-additive) to count as CCs.

This List Changes Annually

The CC Exclusion List is updated every October 1 with the IPPS Final Rule. Always verify your encoder reflects the current FY table. Do not rely on prior-year exclusion knowledge.

Common Exclusion Logic Examples

Principal Diagnosis	Excluded CC/MCC	Reason
N18.6 ESRD	Z99.2 Dialysis dependence	Redundant — ESRD implies dialysis
I21.9 AMI	I25.10 Coronary artery disease	Integral relationship
J18.9 Pneumonia	J96.00 Respiratory failure	May be excluded as expected complication
K74.60 Cirrhosis	K72.10 Chronic hepatic failure	Integral manifestation
A41.9 Sepsis	R65.10 SIRS	SIRS is definitional component of sepsis

Encoder Dependence

Your encoder (3M, Optum, etc.) applies the CC Exclusion List automatically. The coder’s job is to verify that the exclusion makes clinical sense and that no data entry error is causing an incorrect exclusion.

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🏥 POA and HAC Interaction

Present on Admission (POA) Indicators

Indicator	Meaning	CC/MCC Effect
Y	Present at time of admission	Qualifies for CC/MCC
N	Not present at admission; developed during stay	Excluded from CC/MCC if it is a HAC
U	Unknown; insufficient documentation	Does NOT qualify for CC/MCC
W	Clinically undetermined; not known until after admission	Qualifies for CC/MCC
1	Exempt from POA reporting (exempt list)	Qualifies for CC/MCC

Hospital-Acquired Conditions (HACs)

HACs are conditions CMS has identified as preventable complications. If a condition is both a HAC and POA = N, it is excluded from CC/MCC logic, meaning:

• The condition is still coded
• It does NOT contribute to a higher DRG tier
• The hospital may face additional payment penalties

Key HAC Categories (partial list):

HAC	Diagnosis Examples
Pressure Ulcers	L89.xx3, L89.xx4, L89.xx0 (Stage 3/4/Unstageable)
Falls & Trauma	S72.001A Hip fracture after fall during stay
Catheter-Associated UTI	T83.511A + N39.0
Central Line Infections	T80.211A
Surgical Site Infections	Specific post-procedure codes
Glycemic Control	E11.649 Hyperglycemia developed in hospital
DVT/PE post-orthopedic	I26.09, I82.401

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🔴 High-Value MCCs — Universal

These MCCs appear across nearly all MDCs and DRGs. Capturing them when documented and supported is a top priority.

Code	Description	Clinical Trigger
A41.9	Sepsis, unspecified organism	SIRS + infection; organism unknown
A41.51	Sepsis due to E. coli	Positive culture; urosepsis scenarios
A41.01	Sepsis due to MSSA	Culture-positive Staph
A41.02	Sepsis due to MRSA	MRSA on culture
R65.20	Severe sepsis without septic shock	Sepsis + organ dysfunction
R65.21	Septic shock	Sepsis + vasopressor requirement
J96.01	Acute resp failure with hypoxia	SpO₂ drop; supplemental O₂; BiPAP/vent
J96.02	Acute resp failure with hypercapnia	Elevated CO₂; hypercapnic drive
J96.21	Acute-on-chronic resp failure w/ hypoxia	Known COPD/OSA + acute event
N17.9	Acute kidney injury	Creatinine rise ≥ 0.3 from baseline
N17.0	Acute renal cortical necrosis	Severe AKI variant
G93.41	Metabolic encephalopathy	AMS + metabolic derangement
G92.9	Toxic encephalopathy	AMS + drug/toxin etiology
K72.00	Acute hepatic failure	Elevated LFTs + encephalopathy
K72.10	Chronic hepatic failure	End-stage liver disease
I50.21	Acute systolic heart failure	EF < 40 + acute decompensation
I50.23	Acute-on-chronic systolic HF	Known CHF + acute exacerbation
I50.31	Acute diastolic heart failure	EF preserved + fluid overload
E43	Severe protein-calorie malnutrition	Albumin < 2.1, BMI < 16, weight loss
D61.9	Aplastic anemia	Bone marrow failure; pancytopenia
G82.50	Quadriplegia, unspecified	Complete cervical SCI
G82.20	Paraplegia, unspecified	Thoracic/lumbar SCI
R57.0	Cardiogenic shock	Pump failure + hypotension
R57.1	Hypovolemic shock	Hemorrhage/volume depletion + shock
T79.4XXA	Traumatic shock, initial encounter	Major trauma context
C80.1	Malignant neoplasm, unspecified	Metastatic disease, primary unknown
I26.09	Pulmonary embolism without acute cor pulmonale	DVT/PE event
I26.01	Septic pulmonary embolism	PE + sepsis etiology
B20	HIV disease	Active HIV (symptomatic AIDS)

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🟡 High-Value CCs — Universal

Code	Description	Clinical Trigger
N18.4	CKD Stage 4	GFR 15-29
N18.5	CKD Stage 5 (pre-dialysis)	GFR < 15
D62	Acute blood loss anemia	Post-surgical or GI bleed with Hgb drop
D50.0	Iron deficiency anemia due to chronic blood loss	Chronic GI or uterine bleeding
D63.1	Anemia in CKD	CKD + low Hgb; erythropoietin use
E44.0	Moderate malnutrition	Albumin 2.1-2.9; moderate weight loss
E44.1	Mild malnutrition	Albumin 3.0-3.4; mild weight loss
E87.1	Hyponatremia	Na < 135; treated with restriction/hypertonic
E86.0	Dehydration	IV fluids for volume deficit
F17.210	Nicotine dependence, cigarettes	Active smoker; anesthesia risk documentation
G47.33	Obstructive sleep apnea	PSG-confirmed; CPAP use
I10	Essential hypertension	When separately evaluated/treated
I48.0	Paroxysmal atrial fibrillation	New-onset or rate-controlled during stay
I48.2	Chronic atrial fibrillation	Ongoing; anticoagulation managed
E11.65	T2DM with hyperglycemia	BG management required during stay
E11.649	T2DM with hypoglycemia, without coma	Hypoglycemic episode treated
L89.xx2	Pressure injury, Stage 2	Partial thickness wound
L89.xx6	Deep tissue pressure injury	Purple/maroon discoloration
Z79.01	Long-term use of anticoagulants	Warfarin/DOAC; INR monitoring
Z79.4	Long-term use of insulin	Type 1 or insulin-dependent T2DM
J44.1	COPD with acute exacerbation	Baseline COPD + worsening
K92.1	Melena	GI bleed with black stool
K57.30	Diverticulosis of LI without perforation	Incidental finding treated/monitored
T36-T50	Drug poisoning/adverse effect (various)	Medication-induced complication

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🫘 Urology-Specific CC/MCC Table

Code	Description	CC/MCC	Notes
N17.9	Acute kidney injury	MCC	Ubiquitous in urology; post-obstructive AKI
N18.5	CKD Stage 5	MCC	Pre-ESRD; critical to document stage
N18.6	ESRD	MCC	Dialysis-dependent; may be PDx or SDx
N13.30	Obstructive uropathy, unspecified	CC	Hydronephrosis without infection
N13.6	Pyonephrosis	MCC	Infected obstruction — query for sepsis also
A41.51	Sepsis due to E. coli	MCC	Most common urosepsis organism
A41.59	Sepsis, other gram-negative	MCC	Klebsiella, Proteus — culture-confirm
T83.511A	Infection of indwelling urethral catheter	CC	CAUTI; POA critical
T83.518A	Infection of other urinary catheter	CC	Nephrostomy, suprapubic
N99.510	Cystostomy hemorrhage	CC	Post-procedure complication
C67.9	Malignant neoplasm of bladder, unspec	CC	Oncology cases; radical cystectomy driver
C64.1	Malignant neoplasm of right kidney	CC	Nephrectomy driver
D30.01	Benign neoplasm of right kidney	Non-CC	Usually incidental finding
N40.1	Benign prostatic hyperplasia with LUTS	CC	When specifically evaluated/treated
N32.3	Diverticulum of bladder	Non-CC	Context-dependent
R33.9	Retention of urine, unspecified	Non-CC	Query for underlying cause for CC
T83.09XA	Other mechanical complication of cystostomy catheter	CC	Device complication codes

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👂 ENT/OTO-Specific CC/MCC Table

Code	Description	CC/MCC	Notes
J96.01	Acute resp failure with hypoxia	MCC	Airway obstruction, post-laryngectomy
J95.821	Acute postprocedural resp failure	MCC	Post-op ENT; query if ventilated
J38.4	Edema of larynx	CC	Angioedema, post-op swelling
J38.00	Paralysis of vocal cords, unspecified	CC	Post-thyroid/neck surgery
G47.33	Obstructive sleep apnea	CC	UPPP, tonsil, adenoid cases
C32.0	Malignant neoplasm of glottis	CC	Laryngectomy driver
C32.1	Malignant neoplasm of supraglottis	CC	Supraglottic laryngectomy
C10.9	Malignant neoplasm of oropharynx	CC	Base of tongue, tonsillar
C14.0	Malignant neoplasm of pharynx, unspec	CC	Broad pharyngeal malignancy
A69.0	Necrotizing ulcerative stomatitis	MCC	Ludwig’s angina range
K12.2	Cellulitis and abscess of mouth	CC	Peritonsillar / parapharyngeal abscess
J01.90	Acute sinusitis, unspecified	Non-CC	Usually Non-CC; specify organism if possible
H66.90	Otitis media, unspecified	Non-CC	Specify chronic/suppurative for CC
H66.3X9	Chronic suppurative otitis media	CC	With or without spontaneous rupture
F17.210	Nicotine dependence, cigarettes	CC	Common ENT/head-neck comorbidity
E11.65	T2DM with hyperglycemia	CC	Surgical risk and wound healing relevance
T88.3XXA	Malignant hyperthermia due to anesthesia	MCC	Rare; ENT/general surgery context

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👁️ Ophthalmology-Specific CC/MCC Table

Code	Description	CC/MCC	Notes
H44.001	Purulent endophthalmitis, unspecified eye	CC	Query for sepsis if systemic signs
H44.011	Panophthalmitis, right eye	CC	More severe than endophthalmitis
H59.031	Cataract fragments in vitreous cavity post-proc	CC	Post-op complication
E11.3511	T2DM w/ prolif DR, right eye, w/ mac edema	CC	High specificity; drives surgical DRG
E11.3512	T2DM w/ prolif DR, left eye, w/ mac edema	CC
H40.033x	Angle-closure glaucoma, chronic — see H40.033	CC	Bilateral or unilateral
H30.101	Unspecified chorioretinal inflam — see H30.101	CC	Uveitis range
H33.001	Unspecified retinal detachment with break	CC	Surgical DRG driver in ophthalmology
S05.61XA	Penetrating wound of orbit with FB, right	CC	Orbital trauma with foreign body
Z79.01	Long-term anticoagulant use	CC	Vitreous hemorrhage + anticoagulation
B02.34	Herpes zoster ocular disease	CC	HZO; anterior uveitis, keratitis
A54.33	Gonococcal keratitis	MCC	STI-related ocular infection
E10.3511	T1DM w/ prolif DR, right, w/ mac edema	CC	Specify T1 vs T2 when documented

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🦽 PM&R-Specific CC/MCC Table

Code	Description	CC/MCC	Notes
G82.50	Quadriplegia, unspecified	MCC	Cervical SCI; acute care before IRF
G82.51	C1-C4 complete quadriplegia	MCC	ASIA A classification
G82.54	C5-C7 complete quadriplegia	MCC
G82.20	Paraplegia, unspecified	MCC	Thoracic SCI
G83.4	Cauda equina syndrome	CC/MCC	See G83.4; depends on presentation
G54.4	Lumbosacral root disorders	CC	See G54.4
G35	Multiple sclerosis	CC	Acute relapse in acute care
G12.21	Amyotrophic lateral sclerosis (ALS)	MCC	Progressive; high resource use
R26.89	Other abnormalities of gait	Non-CC	Query for specific movement disorder
M62.81	Muscle weakness, generalized	Non-CC	Query for myopathy specificity
G71.00	Muscular dystrophy, unspecified	MCC	Genetic myopathy
G70.01	Myasthenia gravis with acute exacerbation	MCC	Myasthenic crisis
T14.91XA	Suicide attempt, initial encounter	CC	Trauma/behavioral comorbidity
F32.1	Major depressive disorder, single, moderate	CC	When evaluated and treated
F41.1	Generalized anxiety disorder	CC	When clinically addressed

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📋 CC/MCC by Body System — Quick Reference

System	Top MCCs	Top CCs
Infectious	A41.9, R65.20, R65.21	B20, organism-specific sepsis
Respiratory	J96.01, J96.02, J96.21	J44.1, J95.821
Renal	N17.9, N18.6	N18.4, N18.5, N13.6
Cardiac	I50.21, I50.23, R57.0	I48.0, I50.32, I10
Neurologic	G93.41, G82.50, G82.20	G35, G47.33, F05
GI/Hepatic	K72.00, K72.10	K92.1, K57.30
Hematologic	D61.9	D62, D63.1, D50.0
Metabolic	E43, G93.41	E44.0, E87.1, E86.0
Skin/Wound	L89.xx3, L89.xx4, L89.xx0	L89.xx2, L89.xx6
Musculoskeletal	G82.50, G12.21	G83.4, G35, M62.81

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🛠️ Coder Workflow for CC/MCC Capture

FOR EACH secondary diagnosis documented in the record:

1. Is it separately documented and clinically significant?
   → NO: Do not code
   → YES: Continue

2. Does it meet UHDDS secondary diagnosis criteria?
   (Evaluated, treated, or affected management/nursing care)
   → NO: Do not code
   → YES: Continue

3. Is it on the CC/MCC designation list?
   → Check encoder CC/MCC designation field
   → If MCC or CC: flag for review

4. Is it on the CC Exclusion List for the PDx?
   → Encoder will apply automatically
   → Verify exclusion is clinically logical

5. What is the POA indicator?
   → Y/W/1: Qualifies for CC/MCC status
   → N: Check HAC list — if HAC, does NOT qualify
   → U: Does NOT qualify

6. Is there a documentation gap that requires a query?
   → Clinical indicators present but diagnosis not explicit?
   → Open CDI query per [[CDI_Query_Templates]]

7. Verify final DRG tier reflects captured CC/MCC

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🔗 Related Notes

• MS-DRG_Overview
• CDI Query Templates
• MDC 11 - Urology
• MDC 03 - ENT
• MDC 02 - Eye
• HAC_List
• POA_Indicator_Guide
• G83.4
• G54.4
• N17.9
• A41.9

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CC/MCC designations update annually with CMS IPPS Final Rule (October 1). Verify all designations against the current FY CMS CC/MCC table in your encoder.