🚨 HAC List — Hospital-Acquired Conditions Reference

One-Line Definition

Hospital-Acquired Conditions (HACs) are conditions that CMS has determined are: (1) high cost or high volume; (2) result in the assignment of a higher-paying DRG; and (3) could reasonably have been prevented through evidence-based clinical practice — and therefore, when not present on admission (POA = N), are excluded from qualifying as a CC or MCC, eliminating their reimbursement impact.

---

📌 Why This Matters to Coders

HACs sit at the crossroads of coding accuracy, compliance, and quality reporting. A coder who incorrectly assigns POA = Y to a HAC that developed during the hospital stay is not just inflating the DRG — they are potentially shielding the hospital from a rightful HAC penalty and misrepresenting patient safety data. Conversely, assigning POA = N to a condition that was genuinely present at admission inappropriately deflates DRG reimbursement and misclassifies a pre-existing condition as a hospital error.

Core Principle

HACs are not a list of codes you avoid coding — they are a list of conditions you code accurately with precise POA documentation. The condition is always coded. The POA indicator determines whether it qualifies as a CC/MCC and whether the HAC program is triggered.

---

🗂️ Section Index

1. 📖 Background & Program Structure
2. ⚙️ How the HAC Payment Mechanism Works
3. 📋 HAC Category 1 — Foreign Object Retained After Surgery
4. 📋 HAC Category 2 — Air Embolism
5. 📋 HAC Category 3 — Blood Incompatibility
6. 📋 HAC Category 4 — Pressure Ulcers / Injuries
7. 📋 HAC Category 5 — Falls and Trauma
8. 📋 HAC Category 6 — Manifestations of Poor Glycemic Control
9. 📋 HAC Category 7 — Catheter-Associated UTI (CAUTI)
10. 📋 HAC Category 8 — Vascular Catheter-Associated Infections
11. 📋 HAC Category 9 — Surgical Site Infections
12. 📋 HAC Category 10 — DVT/PE Post-Orthopedic
13. 📋 HAC Category 11 — Iatrogenic Pneumothorax with Venous Catheter
14. 🏥 HAC Reduction Program — The Aggregate Penalty
15. 🧪 Coding Scenarios — HAC Applied
16. 🛠️ Coder Workflow for HAC Conditions
17. 📚 References & Resources

---

📖 Background & Program Structure

The HAC program was created by the Deficit Reduction Act of 2005 and implemented in FY2009. Congress directed CMS to identify conditions that: are high-cost or high-volume, result in higher DRG payment when present, and are reasonably preventable through evidence-based care. When these conditions are acquired during the hospital stay, they should not generate a reimbursement windfall for the hospital.

Two Separate HAC Programs

HAC Payment Adjustment vs HAC Reduction Program — Not the Same

There are two distinct but related HAC programs:

Program	What It Does	Mechanism
HAC Payment Adjustment Policy	Removes CC/MCC status from individual HAC claims	Applied at the individual claim level; POA = N triggers removal
HAC Reduction Program (HACRP)	Reduces all IPPS payments by 1% for hospitals in worst quartile for HAC rates	Applied at the hospital level; aggregate quality measure

The HAC Payment Adjustment affects your individual coding work directly. The HACRP affects hospital-wide payment based on aggregate HAC performance.

HAC Selection Criteria (Statutory)

To be designated as a HAC, the condition must be:

1. High cost OR high volume
2. Result in the assignment of a higher-paying MS-DRG when present as a secondary diagnosis
3. Reasonably preventable through the application of evidence-based guidelines

---

⚙️ How the HAC Payment Mechanism Works

Diagnosis coded with POA = N
↓
Is the condition on the HAC list?
↓ YES
Is there a secondary diagnosis present that elevates the DRG?
↓ YES
CMS removes the CC/MCC designation from that secondary diagnosis
↓
DRG reverts to the lower-tier (as if the CC/MCC was not present)
↓
Hospital receives lower DRG payment
↓
HAC event may also be reported to HACRP quality database

The Condition Is Still Coded — Just Not a CC/MCC

When a HAC is triggered (POA = N, condition on HAC list), the ICD-10-CM diagnosis code is still required and must appear on the claim. What changes is that the grouper ignores that code for DRG-tier purposes. The code still populates quality reports, PEPPER data, and external benchmarking.

---

📋 HAC Category 1 — Foreign Object Retained After Surgery

HAC Definition: A foreign object (sponge, needle, instrument) unintentionally left in a patient after a procedure.

Code	Description	POA Consideration
T81.500A	Unspecified complication of foreign body accidentally left in body, initial encounter	Always POA = N — foreign body left during procedure
T81.501A	Adhesion due to foreign body — initial encounter	POA = N
T81.508A	Other complication of foreign body left during procedure	POA = N
T81.509A	Unspecified complication, foreign body left	POA = N

Never POA = Y

By definition, foreign objects retained after surgery are always acquired during the hospital stay. These will always be POA = N. Always code with the appropriate episode-of-care 7th character (A = initial, D = subsequent, S = sequela).

---

📋 HAC Category 2 — Air Embolism

HAC Definition: Iatrogenic air embolism — air introduced into the vasculature through a medical procedure (central line placement, IV infusion, contrast injection).

Code	Description
T80.0XXA	Air embolism following infusion, transfusion, therapeutic injection
T81.718A	Complication of other vascular surgery — air embolism
T81.71XA	Complication of infusion — air embolism

Distinguish from Pulmonary Embolism

Iatrogenic air embolism (T80.0xxA) is distinct from thrombotic pulmonary embolism (I26.xx). PE from DVT is in HAC Category 10 (post-orthopedic only), not Category 2. Iatrogenic air embolism applies across all services.

---

📋 HAC Category 3 — Blood Incompatibility

HAC Definition: Transfusion of ABO-incompatible blood products; Rh incompatibility reactions.

Code	Description
T80.30XA	ABO incompatibility reaction, unspecified
T80.310A	ABO incompatibility with acute hemolytic transfusion reaction
T80.311A	ABO incompatibility with delayed hemolytic transfusion reaction
T80.39XA	Other ABO incompatibility reaction
T80.40XA	Rh incompatibility reaction, unspecified
T80.410A	Rh incompatibility with acute hemolytic transfusion reaction

Always POA = N — Preventable Never-Events

Blood incompatibility reactions are considered never-events — events that should never occur with proper blood bank protocols. Always POA = N by definition.

---

📋 HAC Category 4 — Pressure Ulcers / Injuries

HAC Definition: Stage 3, Stage 4, and Unstageable pressure injuries that were NOT present at the time of hospital admission.

This is the highest-volume HAC category and the most frequently coded incorrectly.

Code	Description	CC/MCC Status	HAC Triggered if POA = N?
L89.XX3	Pressure ulcer, Stage 3	MCC	✅ Yes
L89.XX4	Pressure ulcer, Stage 4	MCC	✅ Yes
L89.XX0	Pressure ulcer, Unstageable	MCC	✅ Yes
L89.XX2	Pressure ulcer, Stage 2	CC	❌ Not a HAC
L89.XX6	Deep tissue pressure injury	CC	❌ Not a HAC
L89.XX1	Pressure ulcer, Stage 1	Non-CC	❌ Not a HAC

Stage 2 Is NOT a HAC — Stage 3/4/Unstageable Are

Only Stage 3, Stage 4, and Unstageable pressure injuries are on the HAC list. Stage 2 and deep tissue injuries are NOT HACs — they are CCs, but their POA indicator does not trigger the HAC mechanism. This distinction is critical for accurate coding.

Common Pressure Ulcer Anatomical Sites (xx = site code)

Site Value	Location
00-09	Elbow (right/left/bilateral/unspecified)
10-19	Upper back
20-29	Coccyx / sacral region
30-39	Hip (right/left)
40-49	Buttock (right/left)
50-59	Ankle (right/left)
60-69	Heel (right/left)
890-899	Other site
900-909	Unspecified site

Sacral and Heel Are Highest Volume

The most commonly coded pressure injury sites in inpatient settings are sacral/coccyx (L89.150-L89.159) and heel (L89.600-L89.609). Know these code ranges by memory for efficient abstraction.

---

📋 HAC Category 5 — Falls and Trauma

HAC Definition: Fractures, dislocations, intracranial injuries, crushing injuries, burns, or other trauma that occur as a result of a fall or other in-hospital event.

Condition Category	Example Codes
Fractures from falls	S72.001A Femoral neck fracture, initial; S22.xx Rib fractures
Intracranial injury	S06.0X0A Concussion, initial; S06.4X0A Epidural hemorrhage
Dislocations	S43.006A Shoulder dislocation, initial
Burns	T20.xx-T32.xx — burns acquired in hospital setting
Crush injuries	S07.xx, S17.xx

Falls Must Be In-Hospital

HAC Category 5 applies to in-hospital falls and trauma. If a patient was admitted for a hip fracture from a fall that occurred at home, that is POA = Y (present at admission) and is NOT a HAC. The HAC is triggered only when the fall/trauma occurs during the hospital stay.

---

📋 HAC Category 6 — Manifestations of Poor Glycemic Control

HAC Definition: Hypoglycemic coma, diabetic ketoacidosis (DKA), hyperglycemic hyperosmolar state, or other glycemic control failures that develop during the hospital stay.

Code	Description	HAC Triggered if POA = N?
E11.641	T2DM with hypoglycemia with coma	✅ Yes
E11.649	T2DM with hypoglycemia without coma	✅ Yes
E10.641	T1DM with hypoglycemia with coma	✅ Yes
E13.641	Other DM with hypoglycemia with coma	✅ Yes
E11.00	T2DM with hyperosmolarity without NKHHC	✅ Yes
E11.01	T2DM with hyperosmolarity with coma	✅ Yes
E10.10	T1DM with DKA without coma	✅ Yes
E10.11	T1DM with DKA with coma	✅ Yes
E11.10	T2DM with DKA without coma	✅ Yes

Pre-Existing DKA May Be POA = Y

If a patient is admitted for DKA (DKA drove the admission), the DKA code is POA = Y and is not a HAC. The HAC only applies when DKA or hypoglycemia develops during a hospitalization for an unrelated condition.

---

📋 HAC Category 7 — Catheter-Associated UTI (CAUTI)

HAC Definition: Urinary tract infection attributable to an indwelling urinary catheter placed during the hospital stay.

Code Combination	Description
T83.511A	Infection of indwelling urethral catheter — initial encounter
T83.518A	Infection of other urinary catheter (suprapubic, nephrostomy)
+ N39.0	UTI — coded as additional diagnosis

CAUTI Is One of the Highest-Volume HACs in Urology

Urology patients have extremely high catheter utilization. Every CAUTI POA assignment requires documentation review. See POA Indicator Guide for detailed CAUTI POA workflow. Key question: Was the catheter placed before or after admission? Was infection present at admission or did it develop during stay?

CAUTI POA Decision Tree

Was a urinary catheter in place at the time of admission?

↓ YES

Was a UTI documented at or before the time of admission?

↓ YES → POA = Y (CAUTI HAC NOT triggered)

↓ NO → UTI developed during stay → POA = N (CAUTI HAC triggered)

↓ NO (catheter placed after admission)

UTI develops during stay with catheter in place → POA = N (CAUTI HAC triggered)

---

📋 HAC Category 8 — Vascular Catheter-Associated Infections

HAC Definition: Bloodstream infections associated with central venous catheters (CVCs) placed during the hospital stay.

Code	Description
T80.211A	Bloodstream infection due to central venous catheter — initial
T80.212A	Local infection due to central venous catheter
T80.218A	Other infection due to central venous catheter
T80.219A	Unspecified infection due to central venous catheter

Central Line vs Peripheral Line

HAC Category 8 applies specifically to central venous catheters (CVCs, PICCs, ports, dialysis catheters). Peripheral IV site infections are not on the HAC list, though they are still codeable complications.

---

📋 HAC Category 9 — Surgical Site Infections

HAC Definition: Surgical site infections (SSIs) following specific high-volume procedures. Not all SSIs are HACs — only those following the designated procedures.

Designated Procedure Categories

Procedure Category	Common ICD-10-PCS Procedures
Cardiac device procedures	AICD, pacemaker implantation
Bariatric surgery	Roux-en-Y, sleeve gastrectomy
Orthopedic procedures	THA, TKA, spinal fusion
Cardiac surgery (CABG)	Coronary artery bypass
Colon surgery	Colectomy, colostomy
Hysterectomy (abdominal)	TAH

SSI Code Examples

Code	Description
T84.50XA	Infection of internal joint prosthesis — initial
T84.51XA	Infection of internal fixation device — initial
T84.54XA	Infection of cardiac pacemaker pocket
T81.4XXA	Infection following a procedure — unspecified
T81.40XA	Superficial SSI following procedure
T81.41XA	Deep SSI following a procedure
T81.42XA	SSI involving organ/space

Specify Depth When Documented

CMS and quality reporting programs distinguish between superficial (T81.40XA), deep (T81.41XA), and organ/space (T81.42XA) SSIs. When the operative or wound care notes specify depth, use the specific code. Default to unspecified only when depth is not documented.

---

📋 HAC Category 10 — DVT/PE Following Total Knee or Hip Replacement

HAC Definition: Deep vein thrombosis or pulmonary embolism following elective total knee arthroplasty (TKA) or total hip arthroplasty (THA).

Code	Description
I26.01	Septic pulmonary embolism with acute cor pulmonale
I26.09	Other pulmonary embolism with acute cor pulmonale
I26.90	Pulmonary embolism without acute cor pulmonale
I82.401	Acute DVT of unspecified deep vein of right lower extremity
I82.411	Acute DVT, right femoral vein
I82.421	Acute DVT, right iliac vein
I82.431	Acute DVT, right popliteal vein
I82.441	Acute DVT, right tibial vein

Orthopedic-Specific — Not All DVT/PE

HAC Category 10 applies only to DVT/PE following TKA or THA. DVT/PE occurring after other surgeries (e.g., post-prostatectomy, post-colorectal) is not a HAC — it is still coded with appropriate POA, and if POA = Y, it qualifies as CC/MCC normally.

---

📋 HAC Category 11 — Iatrogenic Pneumothorax with Venous Catheterization

HAC Definition: Pneumothorax occurring as a complication of central venous catheter placement.

Code	Description
J95.811	Postprocedural pneumothorax
J95.812	Postprocedural air leak

This HAC Is Approach-Specific

Iatrogenic pneumothorax is most commonly associated with subclavian or internal jugular CVC insertion. Confirm the pneumothorax was attributable to the vascular catheter procedure — not to a separate thoracic procedure or underlying pulmonary disease — before applying HAC Category 11.

---

🏥 HAC Reduction Program — The Aggregate Penalty

Beyond the individual claim-level payment adjustment, hospitals face the HAC Reduction Program (HACRP) — a separate, aggregate quality penalty.

How the HACRP Works

Element	Detail
Measurement	CMS measures hospital-wide HAC rates using two domain scores
Domain 1	AHRQ Patient Safety Indicator (PSI) composite score
Domain 2	CDC National Healthcare Safety Network (NHSN) infection measures (CLABSI, CAUTI, SSI, MRSA, C. diff)
Threshold	Hospitals in the worst-performing quartile (25th percentile) are penalized
Penalty	1% reduction applied to ALL Medicare IPPS payments for the fiscal year
Effective Date	Annual determination; applied the following fiscal year

1% of All IPPS Revenue Is a Large Number

For a large academic medical center with **$300M+\ast \ast in\ast \ast MedicareIPPSrevenue\ast \ast ,a1$3M+ in reduced payments for the entire year. This is why C-suite leadership cares deeply about HAC rates — and why accurate POA coding is not just a coding quality issue.

HACRP vs Individual Claim HAC Adjustment

Feature	Individual Claim HAC Adjustment	HACRP
Trigger	Specific HAC code with POA = N	Aggregate quality score
Effect	That diagnosis ≠ CC/MCC on that claim	1% of ALL IPPS payments
Timing	Real-time at claim processing	Annual fiscal year determination
Coder Impact	Direct — POA assignment	Indirect — aggregate HAC rate

---

🧪 Coding Scenarios — HAC Applied

Scenario 1: Stage 3 Pressure Ulcer — Timing Unknown

Facts: 84M admitted for pneumonia. Nursing admission assessment: “skin intact, no wounds.” On hospital day 5, wound care consult documents Stage 3 sacral pressure ulcer.

Code	POA	Rationale
J18.9	Y	Pneumonia — PDx, reason for admission
L89.153	N	Stage 3 sacral pressure ulcer — documented first on day 5; admission skin assessment documented intact skin

HAC Result: Stage 3 pressure ulcer HAC triggered. MCC removed. Hospital’s HACRP domain 1 score affected.

---

Scenario 2: CAUTI — Catheter From SNF

Facts: 72F admitted from SNF with existing Foley catheter. UA on admission: positive for E. coli. Culture confirmed UTI. Documented in ED triage note.

Code	POA	Rationale
N39.0	Y	UTI documented in ED at admission
T83.511A	Y	CAUTI — catheter was in place at admission AND infection confirmed at admission

HAC Result: POA = Y → CAUTI HAC NOT triggered → CC qualifies normally ✅

---

Scenario 3: DVT After TKA

Facts: 65M admitted for elective right TKA. Post-op day 3: bilateral leg ultrasound confirms right popliteal DVT.

Code	POA	Rationale
Z96.641	Y	Presence of right artificial knee joint — status post TKA
I82.431	N	Acute DVT, right popliteal vein — developed post-op day 3; no DVT at admission

HAC Result: HAC Category 10 triggered (DVT post-TKA). DVT does NOT qualify as CC/MCC. Hospital HACRP Domain 2 score affected via NHSN reporting.

---

Scenario 4: Hypoglycemic Episode — Insulin Administration Error

Facts: 58F admitted for COPD exacerbation. T2DM managed with insulin during stay. On day 2, nursing documents hypoglycemic episode (BG 42); patient unresponsive briefly; dextrose administered.

Code	POA	Rationale
J44.1	Y	COPD with acute exacerbation — PDx
E11.641	N	T2DM with hypoglycemia with coma — developed during stay; in-hospital insulin management event
E11.9	Y	T2DM — chronic, pre-existing

HAC Result: HAC Category 6 triggered (manifestation of poor glycemic control). E11.641 does NOT qualify as CC. Hospital glycemic control quality metrics affected.

---

Scenario 5: Retained Surgical Sponge

Facts: 47M admitted for open sigmoid colectomy. Post-op day 2 abdominal X-ray confirms retained laparotomy sponge. Return to OR for removal.

Code	POA	Rationale
K63.5	Y	Polyp of colon — PDx
0DBN0ZZ	Proc	Resection sigmoid colon, open
T81.500A	N	Foreign body (sponge) retained after surgery — by definition POA = N

HAC Result: HAC Category 1 triggered. Never-event. Does NOT qualify as CC/MCC. Mandatory reportable event at most institutions independent of HAC program.

---

🛠️ Coder Workflow for HAC Conditions

FOR EACH secondary diagnosis coded:

1. CODE the condition accurately with full specificity
→ Do not avoid coding HAC-listed conditions
→ Accurate coding is mandatory regardless of HAC designation

2. ASSIGN the POA indicator
→ Review entire record: ED notes, nursing admission assessment,
H&P, progress notes, procedure reports
→ Apply POA logic per [[POA_Indicator_Guide]]
→ When uncertain on a HAC-listed condition → QUERY before defaulting to U

3. CHECK the HAC list
→ Is this diagnosis on one of the 11 HAC categories?
→ Your encoder will flag HAC-designated codes automatically
→ Confirm HAC category applies to this clinical scenario

4. VERIFY the POA + HAC interaction
→ POA = Y → condition qualifies as CC/MCC normally; HAC not triggered
→ POA = N → HAC triggered; CC/MCC status removed by grouper
→ POA = U → treated same as N; CC/MCC removed; HAC triggered
→ POA = W → qualifies as CC/MCC; HAC not triggered
→ POA = 1 (exempt) → qualifies as CC/MCC; HAC not applicable

5. CONFIRM DRG impact in your encoder
→ After HAC designation applied, re-verify DRG tier
→ If DRG dropped due to HAC exclusion, document in your abstraction notes

6. FLAG for CDI review if POA is ambiguous
→ Pressure ulcer timing not documented in admission skin assessment?
→ DVT — was pre-admission ultrasound performed? Any prior history?
→ AKI — admission creatinine elevated? Query timing
→ Initiate query using [[CDI Query Templates]] for POA timing clarification

7. DOCUMENT your POA rationale
→ For every HAC-listed diagnosis, note the source document
that supports your POA determination
→ Audit-defensible documentation starts at abstraction

---

📋 HAC Quick Reference — All 11 Categories

HAC #	Category	Key Codes	Always POA = N?	CC/MCC Lost if POA = N
1	Foreign Object Retained After Surgery	T81.500A-T81.509A	✅ Yes	MCC
2	Air Embolism	T80.0xxA	✅ Yes	MCC
3	Blood Incompatibility	T80.30xA-T80.41XA	✅ Yes	MCC
4	Pressure Ulcers Stage 3/4/Unstageable	L89.xx3, L89.xx4, L89.xx0	❌ POA-dependent	MCC
5	Falls and Trauma	S72.001A, S06.xx, others	❌ POA-dependent	CC/MCC varies
6	Glycemic Control Failures	E11.641, E10.10, E11.00	❌ POA-dependent	CC
7	CAUTI	T83.511A + N39.0	❌ POA-dependent	CC
8	Vascular Catheter Infections (CLABSI)	T80.211A-T80.219A	❌ POA-dependent	MCC
9	Surgical Site Infections (specific procedures)	T81.40XA-T81.42XA, T84.50XA	❌ POA-dependent	CC/MCC varies
10	DVT/PE Post-TKA/THA	I82.401, I82.431, I26.09	❌ POA-dependent	MCC
11	Iatrogenic Pneumothorax w/ Venous Cath	J95.811, J95.812	❌ POA-dependent	CC

---

📚 References & Resources

Resource	Description	URL
CMS HAC Reduction Program	Official program overview, HAC list, scoring methodology	cms.gov/Medicare/Medicare-Fee-for-Service-Payment/AcuteInpatientPPS/HAC-Reduction-Program
CMS HAC Payment Adjustment	Individual claim-level HAC payment adjustment policy	cms.gov/Medicare/Coding/ICD10
AHRQ PSI Composite Measures	Domain 1 quality metrics for HACRP	qualityindicators.ahrq.gov
CDC NHSN	Domain 2 infection surveillance data (CLABSI, CAUTI, SSI)	cdc.gov/nhsn
IPPS Final Rule FY2025	Annual HAC list updates; effective October 1	federalregister.gov
AHIMA HAC Coding Guidance	Coding and POA best practices for HAC conditions	ahima.org
AHA Coding Clinic	Official Q&A on HAC-related coding scenarios	ahacentraloffice.org
AAPC CIC Study Guide	HAC and POA content for inpatient certification	aapc.com

---

🔗 Related Notes

• POA Indicator Guide — POA assignment logic; HAC-POA interaction workflow
• CC-MCC Reference — CC/MCC designation; HAC exclusion mechanism
• MS-DRG Overview — DRG grouper logic; how HAC removes CC/MCC from tier calculation
• IPPS Payment Overview — HAC Reduction Program 1% aggregate penalty
• UHDDS Principal Diagnosis — PDx is always POA = Y; HAC applies only to secondary dx
• CDI Query Templates — Query templates for POA timing clarification
• MDC 11 - Urology — CAUTI HAC context; catheter use in urology
• MDC 03 - ENT — Post-op complication HAC scenarios; SSI in head/neck surgery
• MDC 02 - Eye — Post-procedural complication POA; HAC in surgical ophthalmology
• L89.153 — Stage 3 sacral pressure ulcer — HAC Category 4
• T83.511A — CAUTI — HAC Category 7
• I82.431 — DVT right popliteal — HAC Category 10
• T80.211A — CLABSI — HAC Category 8
• T81.500A — Retained foreign object — HAC Category 1

---

HAC categories, designated procedures, and qualifying diagnosis codes update annually with the CMS IPPS Final Rule (October 1). Verify current-year HAC lists in your encoder at each fiscal year transition. The HACRP domain scoring methodology may also be updated annually.