What is ICD-10 code E06.0?

E06.0 is the ICD-10-CM diagnosis code for Acute thyroiditis. Sudden inflammation of the thyroid gland, typically caused by infection or immune response. It belongs to the ICD-10-CM chapter for endocrine, nutritional and metabolic diseases (e00-e89). E06.0 is a billable code, meaning it can be reported on a claim as a primary or secondary diagnosis when supported by documentation. E06.0 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. E06.0 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. E06.0 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.

What is the V28 vs V24 difference for E06.0?

E06.0 does not map to a payment HCC under either the CMS-HCC V28 risk adjustment model or the older V24 model. V28 reached 100% phase-in for payment year 2026, replacing V24 which was used during the PY2024–PY2025 transition. Because neither community model rewards E06.0 with a risk adjustment factor, it contributes zero to a Medicare Advantage beneficiary's V28/V24 community RAF score in either version. It does, however, map under the Part D RxHCC model (Thyroid and Parathyroid Disorders), which affects the ESRD and/or Part D (RxHCC) risk scores. Coders should check whether provider documentation supports a more specific child code that does map to a community payment HCC.

What should coders know when reporting E06.0?

Specify the type of acute thyroiditis if documented (viral, bacterial, autoimmune, or post-partum) Distinguish from chronic thyroiditis (E06.1) and other thyroid inflammation conditions

2026 ICD-10-CM E06.0: Acute thyroiditis

ICD-10-CM Code View

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Code lookupE06.0Effective periodFY2026 Apr Update (Apr 1-Sep 30)

FY 2026 Apr update / Endocrine, nutritional and metabolic diseases (E00-E89) / Disorders of thyroid gland (E00-E07)

E06.0

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

Acute thyroiditis

Sudden inflammation of the thyroid gland, typically caused by infection or immune response.

Buddy Insight

CMS-HCC V28

N/A

—

Not risk-adjusted for this model/period.

Not mapped

CMS-HCC V24

N/A

—

Not risk-adjusted for this model/period.

Not mapped

ACA/HHS

N/A

—

Not risk-adjusted for this model/period.

Not mapped

ESRD/PACE

N/A

—

Not risk-adjusted for this model/period.

Not mapped

RXHCC

Mapped

HCC 44

Thyroid and Parathyroid Disor...

RAF 0.070

Code Book Path

Official

E06Thyroiditis

E06.0Acute thyroiditis

Inclusion Terms

Official

Abscess of thyroid
Pyogenic thyroiditis
Suppurative thyroiditis

Excludes 2

Official

ICD-10-CM does not list Excludes 2 notes for E06.0 in this effective period.

Related Child Codes

Official

E06.1Subacute thyroiditis

E06.2Chronic thyroiditis with transient thyrotoxicosis

E06.3Autoimmune thyroiditis

E06.4Drug-induced thyroiditis

E06.5Other chronic thyroiditis

Includes

Official

ICD-10-CM does not list Includes notes for E06.0 in this effective period.

Excludes 1

Official

postpartum thyroiditis (O90.5)

Code First

Official

ICD-10-CM does not list Code First sequencing instructions for E06.0 in this effective period.

Use Additional

Official

code (B95-B97) to identify infectious agent.

Code Also

Official

ICD-10-CM does not list Code Also instructions for E06.0 in this effective period.

Buddy Documentation Tip

HCC Buddy guidance

Document the acute onset of thyroid inflammation, infectious etiology if identified (bacterial culture results), imaging findings (ultrasound or CT showing abscess), and treatment with antibiotics and/or surgical drainage.

Record the patient's immune status and any predisposing anatomic abnormalities.

MEAT Support

HCC Buddy guidance

Record the patient's immune status and any predisposing anatomic abnormalities.

Audit Caution

HCC Buddy guidance

Do not confuse acute suppurative thyroiditis with subacute (de Quervain) thyroiditis, which is viral and self-limited.

Acute thyroiditis is very rare and almost always bacterial, requiring antibiotics rather than anti-inflammatory therapy.

If an abscess is drained, code the procedure separately.

Common Mistakes

HCC Buddy guidance

E06.1: Subacute thyroiditis — viral etiology with granulomatous inflammation, different treatment approach

E06.3: Autoimmune thyroiditis (Hashimoto's) — chronic autoimmune condition, not infectious

E06.9: Thyroiditis unspecified — avoid when acute infectious thyroiditis is clearly documented

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 E06.0 an HCC code?

E06.0 is not in the CMS-HCC V28 or V24 community payment model, but it does map to Thyroid and Parathyroid Disorders under the Part D RxHCC model.

Code: E06.0
Description: Acute thyroiditis
HCC (V28): No CMS-HCC V28 mapping
RAF: —
Billable: Yes
Payment year: 2026

HCC Category Mapping

RxHCCHCC 44, Thyroid and Parathyroid Disorders

0.070

Each model's RAF is its CMS base weight for that model's standard population, so 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 segment, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains in use during the transition and for historical data.

Work E06.0 in the Code Book — tabular path, V28 RAF, and MEAT checklist →

MEAT Criteria for E06.0

For E06.0 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 E06.0 during that encounter, not just copy-forwarded from a problem list.

Coder workflow notes

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What This Code Means

E06.0 is the ICD-10-CM diagnosis code for acute thyroiditis. Sudden inflammation of the thyroid gland, typically caused by infection or immune response. E06.0 sits in the ICD-10-CM chapter for endocrine, nutritional and metabolic diseases (e00-e89), within the section covering disorders of thyroid gland (e00-e07).

E06.0 is a billable ICD-10-CM code but does not map to a payment HCC under the CMS-HCC V28, V24, ESRD, or RxHCC risk adjustment models. It can be reported on Medicare Advantage encounter data submissions but it does not contribute to a beneficiary's RAF score and therefore does not affect risk-adjusted payments to the plan.

This code does not map to a CMS-HCC V28 payment category. Capture depends on documentation that supports the diagnosis; verify the HCC assignment against the current CMS mapping for the applicable payment year. Coders reviewing E06.0 should check whether additional documentation would support a more specific child code in the same hierarchy that does map to a payment HCC, capturing the correct specificity is the highest-impact RAF improvement available within accurate coding.

HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for E06.0 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•Specify the type of acute thyroiditis if documented (viral, bacterial, autoimmune, or post-partum)
•Distinguish from chronic thyroiditis (E06.1) and other thyroid inflammation conditions

Clinical Significance

Acute thyroiditis is a rare, typically bacterial infection of the thyroid gland (suppurative thyroiditis) that presents with severe anterior neck pain, fever, dysphagia, and a tender, swollen thyroid. Unlike other forms of thyroiditis, this condition requires antibiotic therapy and may necessitate surgical drainage of abscess formation. It most commonly occurs in immunocompromised patients or those with pre-existing thyroid disease or piriform sinus fistula.

Documentation Requirements

✓Document the acute onset of thyroid inflammation, infectious etiology if identified (bacterial culture results), imaging findings (ultrasound or CT showing abscess), and treatment with antibiotics and/or surgical drainage.
✓Record the patient's immune status and any predisposing anatomic abnormalities.

Use Additional Code

code (B95-B97) to identify infectious agent.

Commonly Confused Codes

•E06.1: Subacute thyroiditis: viral etiology with granulomatous inflammation, different treatment approach
•E06.3: Autoimmune thyroiditis (Hashimoto's): chronic autoimmune condition, not infectious
•E06.9: Thyroiditis unspecified: avoid when acute infectious thyroiditis is clearly documented