What is ICD-10 code A06.5?

A06.5 is the ICD-10-CM diagnosis code for Amebic lung abscess. It belongs to the ICD-10-CM chapter for certain infectious and parasitic diseases (a00-b99). A06.5 is a billable code, meaning it can be reported on a claim as a primary or secondary diagnosis when supported by documentation. A06.5 is part of the FY2026 ICD-10-CM code set published by the CMS National Center for Health Statistics and used on Medicare, Medicaid, and commercial claims in the United States.

Yes. A06.5 is a billable ICD-10-CM code that can be reported on professional and institutional claims as a primary or secondary diagnosis when the provider documentation supports the specific condition described. Billable codes in ICD-10-CM are coded to the highest level of specificity available for the documented diagnosis. A06.5 is current for fiscal year 2026 and remains in the active CMS ICD-10-CM code set published by the National Center for Health Statistics.

Which HCC does A06.5 map to under V28?

A06.5 maps to CMS-HCC V28 HCC 283 (Empyema, Lung Abscess). The category numbers, labels, and conditions come from the CMS-HCC V28 model file for payment year 2026.

What documentation supports A06.5?

Verify documentation confirms amebic etiology rather than other causes of lung abscess; amebic lung abscess is relatively rare and requires specific diagnostic confirmation Check for documentation of the primary amebic infection site (usually intestinal) as there may be additional codes needed to capture the complete clinical picture Because A06.5 maps to an HCC category, the documentation must satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) before the diagnosis is used for risk adjustment. See the MEAT criteria checklist at /meat-criteria for what Monitor, Evaluate, Assess, or Treat looks like in a note. MEAT is generic documentation evidence, not a payer-specific rule.

2026 ICD-10-CM A06.5: Amebic lung abscess

A06.5 maps to CMS-HCC V28 283. A source-labeled RAF reference is available. Documentation must support MEAT. MEAT criteria · RAF Calculator · free HCC coding tools

ICD-10-CM Code View

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Code lookupA06.5Effective periodFY2026 Apr Update (Apr 1-Sep 30)

FY 2026 Apr update / Certain infectious and parasitic diseases (A00-B99) / Intestinal infectious diseases (A00-A09)

A06.5

Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidance

Amebic lung abscess

A lung abscess (a pocket of pus in the lung) caused by a parasitic infection from amoebas, typically acquired through contaminated food or water. This is a serious infection that can develop when amoebas spread from the intestines to the lungs.

Buddy Insight

Amebic lung abscess is a serious parasitic complication where Entamoeba histolytica, typically from a liver abscess, extends into the pulmonary space.

CMS-HCC V28

Mapped

HCC 283

Empyema, Lung Abscess

Code-level coefficient reference

CMS-HCC V24

Historical

Not used for standard CY2026 Medicare Advantage payment. Select a historical period to review V24.

Not used for CY2026 payment

ACA/HHS

Mapped

HCC 163

HHS-HCC 163 adult, RAF varies...

Code-level coefficient reference

ESRD/PACE

Mapped

HCC 115

Pneumococcal Pneumonia/Empyem...

Code-level coefficient reference

RXHCC

N/A

—

Not risk-adjusted for this model/period.

Not mapped

Code Book Path

Official

A06Amebiasis

A06.5Amebic lung abscess

Inclusion Terms

Official

Amebic abscess of lung (and liver)

Excludes 2

Official

acanthamebiasis (B60.1-)
Naegleriasis (B60.2)

Related Child Codes

Official

A06.0Acute amebic dysentery

A06.1Chronic intestinal amebiasis

A06.2Amebic nondysenteric colitis

A06.3Ameboma of intestine

A06.4Amebic liver abscess

Includes

Official

infection due to Entamoeba histolytica

Excludes 1

Official

other protozoal intestinal diseases (A07.-)

Code First

Official

ICD-10-CM does not list Code First sequencing instructions for A06.5 in this effective period.

Use Additional

Official

ICD-10-CM does not list Use Additional Code instructions for A06.5 in this effective period.

Code Also

Official

ICD-10-CM does not list Code Also instructions for A06.5 in this effective period.

Buddy Documentation Tip

HCC Buddy guidance

Confirmed or suspected Entamoeba histolytica infection with pulmonary involvement

Imaging (CT chest or chest X-ray) demonstrating lung abscess, consolidation, or pleural effusion

Documentation of route of spread (direct extension from hepatic abscess through diaphragm vs. hematogenous)

Serologic testing for E. histolytica (IgG antibodies) or stool antigen testing

MEAT Support

HCC Buddy guidance

Confirmed or suspected Entamoeba histolytica infection with pulmonary involvement

Imaging (CT chest or chest X-ray) demonstrating lung abscess, consolidation, or pleural effusion

Documentation of route of spread (direct extension from hepatic abscess through diaphragm vs. hematogenous)

Serologic testing for E. histolytica (IgG antibodies) or stool antigen testing

Audit Caution

HCC Buddy guidance

Do not assign J85 lung abscess codes when the abscess is amebic in origin — A06.5 is the specific combination code

Amebic lung abscess often coexists with amebic liver abscess (A06.4) — code both when documented

Do not confuse with bacterial lung abscess in a patient who also has intestinal amebiasis — the abscess must be specifically attributed to Entamoeba

Common Mistakes

HCC Buddy guidance

J85.2 (Abscess of lung without pneumonia) — Use A06.5 when the lung abscess is specifically due to amebic infection, not J85.2

A06.4 (Amebic liver abscess) — Code A06.5 for pulmonary extension; if both liver and lung abscesses are present, code both A06.4 and A06.5

A06.0 (Acute amebic dysentery) — A06.0 is for intestinal amebiasis only; A06.5 captures the extraintestinal pulmonary complication

Current with CMS: FY2026 ICD-10-CM Apr 1 update (effective Apr 1 – Sep 30, 2026) · CMS-HCC V28, 100% phased in for payment year 2026. FY2027 code set already staged for October 1, 2026. How HCC Buddy stays current →

Is A06.5 an HCC code?

Yes. A06.5 (Amebic lung abscess) maps to HCC 283, Empyema, Lung Abscess under the CMS-HCC V28 risk adjustment model, with a source-labeled community non-dual aged reference coefficient of 0.204. Source-labeled code-level coefficients are references, not member totals. Actual contribution depends on complete member context, hierarchy and cleanup rules, interactions, and model year. HCC Buddy's RAF Calculator supports CMS-HCC V28 PY2026 and shows no score unless every required source and calculation check passes. It is billable for payment year 2026.

Coder answer: A06.5 is billable and maps to V28 HCC 283, Empyema, Lung Abscess. Open it in the Code Book for the tabular path, RAF, and MEAT checklist.

Code: A06.5
Description: Amebic lung abscess
HCC (V28): HCC 283 — Empyema, Lung Abscess
RAF reference coefficient: 0.204
Billable: Yes
Payment year: 2026

HCC Category Mapping

V28HCC 283, Empyema, Lung Abscess

0.204

ESRDHCC 115, Pneumococcal Pneumonia/Empyema/Lung Abscess

Not separately weighted

These are source-labeled model coefficients, not member totals. A category may still be removed by hierarchy or model cleanup rules. Weights are not directly comparable across models: CMS-HCC V28 and V24 use Community, Non-Dual, Aged; ESRD uses the dialysis continuing-enrollee model; RxHCC is the Part D continuing-enrollee, non-low-income, aged weight (a larger scale than CMS-HCC). ACA/HHS has no single weight — it varies by metal level. Actual per-patient RAF contribution depends on member context, hierarchy and cleanup rules, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains available for historical review.

Work A06.5 in the Code Book — tabular path, V28 RAF reference, and MEAT checklist →

MEAT Criteria for A06.5

For A06.5 to count as a valid HCC diagnosis in a given encounter, the provider's documentation must show MEAT: Monitor, Evaluate, Assess, or Treat. A diagnosis from a prior year does not carry forward automatically, it has to be re-documented and supported each calendar year.

MMonitor: signs, symptoms, disease progression, or lab trending documented in the note
EEvaluate: test results, medication response, or physical findings reviewed by the provider
AAssess: explicit mention in the assessment or plan with acknowledgment of status
TTreat: medication, referral, procedure, therapy, or counseling tied to the diagnosis

Only one of M/E/A/T is required to support the code, but the documentation must be specific enough to show that the provider actually addressed A06.5 during that encounter, not just copy-forwarded from a problem list.

Coder workflow notes

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What This Code Means

A06.5 is the ICD-10-CM diagnosis code for amebic lung abscess. A lung abscess (a pocket of pus in the lung) caused by a parasitic infection from amoebas, typically acquired through contaminated food or water. This is a serious infection that can develop when amoebas spread from the intestines to the lungs. A06.5 sits in the ICD-10-CM chapter for certain infectious and parasitic diseases (a00-b99), within the section covering intestinal infectious diseases (a00-a09).

Under the CMS-HCC V28 risk adjustment model, A06.5 maps to Empyema, Lung Abscess (HCC 283) with a source-labeled community, non-dual, aged reference coefficient of 0.204. No V24 mapping is shown for A06.5; use the applicable model and payment year when reviewing the V28 mapping. V28 is the CMS-HCC risk adjustment model that reached 100% phase-in for payment year 2026, replacing V24 which was used during the PY2024–PY2025 transition. Source-labeled code-level coefficients are references, not member totals. Actual contribution depends on complete member context, hierarchy and cleanup rules, interactions, and model year. HCC Buddy's RAF Calculator supports CMS-HCC V28 PY2026 and shows no score unless every required source and calculation check passes.

Verify documentation confirms amebic etiology rather than other causes of lung abscess; amebic lung abscess is relatively rare and requires specific diagnostic confirmation. Because A06.5 maps to an HCC category, the provider's documentation must satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) before the diagnosis is used for risk adjustment. When documentation is ambiguous, coders should issue a provider query rather than assume the highest-specificity variant.

HCC Buddy maintains structured V28 and V24 mapping, source-labeled coefficient references, and MEAT documentation criteria for A06.5 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•Verify documentation confirms amebic etiology rather than other causes of lung abscess; amebic lung abscess is relatively rare and requires specific diagnostic confirmation
•Check for documentation of the primary amebic infection site (usually intestinal) as there may be additional codes needed to capture the complete clinical picture

Clinical Significance

Amebic lung abscess is a serious parasitic complication where Entamoeba histolytica, typically from a liver abscess, extends into the pulmonary space. This represents advanced amebiasis requiring both antiparasitic therapy and potentially interventional drainage, with significant morbidity if untreated.

Documentation Requirements

✓Confirmed or suspected Entamoeba histolytica infection with pulmonary involvement
✓Imaging (CT chest or chest X-ray) demonstrating lung abscess, consolidation, or pleural effusion
✓Documentation of route of spread (direct extension from hepatic abscess through diaphragm vs. hematogenous)
✓Serologic testing for E. histolytica (IgG antibodies) or stool antigen testing
✓Travel history or epidemiologic risk factors for amebiasis

Commonly Confused Codes

•J85.2 (Abscess of lung without pneumonia): Use A06.5 when the lung abscess is specifically due to amebic infection, not J85.2
•A06.4 (Amebic liver abscess): Code A06.5 for pulmonary extension; if both liver and lung abscesses are present, code both A06.4 and A06.5
•A06.0 (Acute amebic dysentery): A06.0 is for intestinal amebiasis only; A06.5 captures the extraintestinal pulmonary complication