Acute vs History-of: 6 ICD-10 Calls That Decide Whether the HCC Holds Up

The split between an acute condition and a resolved one is where a lot of HCCs quietly fall apart in audit. Acute ischemic stroke, acute MI, acute DVT or PE, and acute respiratory failure each carry an HCC under the CMS-HCC V28 model. The history-of and resolved codes that should replace them once the event is over usually carry nothing. Keep the acute code on a chart six months after the event and the record will not support it. That is one of the most common ways an HCC gets pulled on review.

This is a reference for the six places that call comes up most, the specific ICD-10-CM codes on each side of it, and what each one maps to under V28 (the model that pays for PY2026). It is documentation and audit defense, not a code-it-this-way shortcut. The chart decides which code is correct, every time.

Current as of June 2026. HCC and RAF references use the CMS-HCC V28 model (PY2026, 100% phase-in). Coding-convention references are to the FY2026 ICD-10-CM Official Guidelines for Coding and Reporting (effective 10/1/2025).

Key Takeaways

1. Acute Stroke vs History of Stroke vs Stroke With a Residual Deficit

This is three codes, not two, and that is exactly why it gets miscoded.

I63.- maps to HCC 249, Ischemic or Unspecified Stroke, under V28. The catch is that I63 is an in-the-moment code. It belongs on the encounter where the infarction is being actively managed, not on a routine follow-up six months later.

Once the acute event is over, you land in one of two places. If the patient walked away with no lasting deficit, the code is Z86.73, personal history of transient ischemic attack and cerebral infarction without residual deficits. That carries no HCC. If a deficit remains and it is documented, you code the sequela from the I69 family. Hemiplegia and hemiparesis following cerebral infarction (I69.35-) maps to HCC 253, Hemiplegia/Hemiparesis.

Keeping I63.- on the chart after the patient is stable is the textbook acute-stroke overcode, and it is the pattern an OIG audit report flagged in stroke charts. See our news desk write-up on the OIG stroke overpayment audit for the dated detail. The flip side costs just as much. A patient with real post-stroke weakness coded to plain Z86.73 loses HCC 253 entirely. The unspecified sequela codes (I69.30, I69.20) do not map either, so "sequela of stroke" with no deficit named gets you nothing. The deficit has to be in the note.

2. Acute MI vs Old MI

I21.- is the whole acute MI category, STEMI and NSTEMI alike, and subsequent MI (I22.-) sits with it. All of it maps to HCC 228, Acute Myocardial Infarction, under V28.

The catch is the clock. Per the Official Guidelines, I21 is for an MI 28 days old or less, counting from onset. After that window, the code is I25.2, old myocardial infarction. No HCC. Plain coronary artery disease (I25.10) carries nothing either.

The temptation is to carry I21 onto the next visit because it holds the HCC and old MI does not. That is the error. An I21 on an outpatient note dated two months after the event will not survive a record pull. If the MI is genuinely historical, it is I25.2, and the HCC is simply gone. There is no acute-MI HCC to keep once the event is no longer acute.

3. Acute DVT or PE vs History of Clot

Acute deep vein thrombosis (I82.4-) and acute pulmonary embolism (I26.-) both map to HCC 267, Deep Vein Thrombosis and Pulmonary Embolism, under V28. Relearn this one for V28: in V24 these codes fell under the broader vascular-disease HCCs (107 and 108). V28 gave venous thromboembolism its own dedicated HCC.

The acute code asserts an active clot, the kind a patient is anticoagulated for right now. Once the clot has resolved and the patient is no longer being treated for it, you are at Z86.718, personal history of venous thrombosis and embolism, or Z86.711 for a history of pulmonary embolism. Both carry no HCC.

A patient who finished six months of anticoagulation and came off it does not have an active DVT anymore. Coding I82.4- on that visit to hold HCC 267 is unsupported. The personal-history code is the honest one, and it maps to nothing. The HCC lives and dies with the active clot.

4. Acute vs Chronic Respiratory Failure

Acute respiratory failure (J96.0-), chronic respiratory failure (J96.1-), and acute-on-chronic respiratory failure (J96.2-) all map to the same HCC: HCC 213, Cardio-Respiratory Failure and Shock, under V28.

Because the HCC is identical across all three, this one is not about losing RAF on the wrong choice. It is about whether the acuity you coded is supported. Acute respiratory failure asserts an acute event, with hypoxia or hypercapnia documented, an intervention, the clinical picture of someone in failure. A stable patient on home oxygen for a chronic condition is chronic respiratory failure (J96.1-), and that is the durable code you re-document each year.

Code J96.0- on a stable, chronic patient and the exposure is not a lower HCC. It is the acute label inviting a documentation challenge the chart cannot answer. Match the acuity to the encounter. Chronic respiratory failure is the one that recaptures cleanly visit to visit.

5. Active Pressure Ulcer vs Healed

A pressure ulcer is only an HCC while it is present and staged. Stage 3 (for example L89.143) maps to HCC 381, Pressure Ulcer of Skin with Full Thickness Skin Loss. Stage 4 (for example L89.154) maps to HCC 379, Pressure Ulcer of Skin with Necrosis Through to Muscle, Tendon, or Bone, one of the heavier coefficients on this list.

A completely healed pressure ulcer is not coded at all. Per the Official Guidelines, a pressure ulcer documented as healing is coded to the appropriate stage; one documented as fully healed is not reported. There is no history-of-pressure-ulcer HCC to fall back on.

The high coefficient makes this a frequent audit target, and the audit question is binary. Was the ulcer present and staged at the encounter, in the documentation, or had it healed? Carry a pressure-ulcer code forward on a patient whose skin has healed and you have an HCC that will not hold.

6. Acute Kidney Injury vs Chronic Kidney Disease

Acute kidney injury (N17.-, acute kidney failure) carries no HCC under V28. This is a real V28 change worth flagging. Under V24, acute renal failure mapped to HCC 135. V28 dropped it.

Chronic kidney disease is the durable, risk-adjusted one. Stage 4 (N18.4) maps to HCC 327, Chronic Kidney Disease, Severe (Stage 4). Stage 3 (N18.30) maps to HCC 329, Chronic Kidney Disease, Moderate (Stage 3, Except 3B). Stage 5 and ESRD sit higher.

AKI and CKD are different conditions, not an acute-and-chronic pair of the same thing, but they get conflated because both are "kidney." For risk adjustment the point is blunt: AKI buys you nothing under V28, while staged CKD is one of the conditions you should be recapturing every year. Do not lean on an AKI code expecting it to risk-adjust.

At a Glance

Frequently Asked Questions

How long can I report an acute MI (I21)?

Four weeks. The Official Guidelines limit I21 to an MI 28 days old or less from onset. After that, it is I25.2, old myocardial infarction, which carries no HCC under V28.

Does a personal-history-of-stroke code carry an HCC?

No. Z86.73 (personal history of TIA and cerebral infarction without residual deficits) does not map to any HCC under V28. If the patient has a documented residual deficit, you code the specific I69 sequela instead, which can map. Hemiplegia (I69.35-) maps to HCC 253.

Did acute kidney injury lose its HCC under V28?

Yes. Acute kidney failure (N17.-) carried HCC 135 under V24 but maps to no HCC under V28. Chronic kidney disease (N18.- with a documented stage) is the risk-adjusted code.

A stroke patient still has weakness. What do I code?

Code the documented residual deficit as a sequela of cerebrovascular disease. Hemiplegia or hemiparesis following cerebral infarction (I69.35-) maps to HCC 253. The unspecified sequela codes (I69.30, I69.20) do not map, so the specific deficit has to be documented.

Disclaimer

This article is professional and educational information for risk-adjustment coders, not coding, billing, legal, or medical advice. Code assignment depends on the full medical record and provider documentation. Verify every code against the current ICD-10-CM Official Guidelines, the applicable CMS-HCC model files, and AHA Coding Clinic guidance before you apply it. No provider-patient or advisory relationship is created by reading this.

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