E06.1 is not a CMS-HCC payment code. MEAT criteria · RAF Calculator · free HCC coding tools

ICD-10-CM Code View

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Code lookupE06.1

Effective periodFY2026 Apr Update (Apr 1-Sep 30)

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

E06.1

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

Subacute thyroiditis

Inflammation of the thyroid gland that develops over weeks to months, often following a viral infection, causing temporary thyroid dysfunction.

Buddy Insight

Overview Risk Models Code Book Documentation Audit Notes Edition comparison

CMS-HCC V28

N/A

—

Not risk-adjusted for this model/period.

Not mapped

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

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 Disorders

Code-level coefficient reference

Code Book Path

Official

E06Thyroiditis E06.1Subacute thyroiditis

Inclusion Terms

Official

de Quervain thyroiditis
Giant-cell thyroiditis
Granulomatous thyroiditis
Nonsuppurative thyroiditis
Viral thyroiditis

Excludes 2

Official

No Excludes 2 notes are included in this display for E06.1. Check the code and parent instructions in the Code Book.

Related Codes

Official

E06.0Acute thyroiditis E06.2Chronic thyroiditis with transient thyrotoxicosis E06.3Autoimmune thyroiditis E06.4Drug-induced thyroiditis E06.5Other chronic thyroiditis

Includes

Official

No Includes notes are included in this display for E06.1. Check the code and parent instructions in the Code Book.

Excludes 1

Official

autoimmune thyroiditis (E06.3)
transitory endocrine and metabolic disorders specific to newborn (P70-P74)Inherited from E00-E89, E06
postpartum thyroiditis (O90.5)Inherited from E00-E89, E06

Code First

Official

No Code First sequencing instructions are included in this display for E06.1. Check the code and parent instructions in the Code Book.

Use Additional

Official

No Use Additional Code instructions are included in this display for E06.1. Check the code and parent instructions in the Code Book.

Code Also

Official

No Code Also instructions are included in this display for E06.1. Check the code and parent instructions in the Code Book.

Buddy Documentation Tip

HCC Buddy guidance

Document the temporal relationship to antecedent viral illness, thyroid tenderness and enlargement on examination, laboratory findings (elevated ESR, thyroid function tests), and the current phase of the triphasic course (thyrotoxic, hypothyroid, or recovery).

Record treatment with NSAIDs or corticosteroids if applicable.

MEAT Support

HCC Buddy guidance

Record treatment with NSAIDs or corticosteroids if applicable.

Audit Caution

HCC Buddy guidance

During the thyrotoxic phase, do not separately code hyperthyroidism — the thyrotoxicosis is part of the subacute thyroiditis clinical course.

Similarly, transient hypothyroidism during recovery is part of the natural history and should not prompt separate hypothyroidism coding unless it becomes permanent.

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 E06.1 an HCC code?

Code: E06.1
Description: Subacute thyroiditis
HCC (V28): No CMS-HCC V28 mapping
RAF reference coefficient: —
Billable: Yes
Payment year: 2026

HCC Category Mapping

RxHCCHCC 44, Thyroid Disorders

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 E06.1 in the Code Book — tabular path, V28 RAF reference, and MEAT checklist →

MEAT review for E06.1

For E06.1, confirm that the documentation supports the diagnosis and meets the applicable coding, encounter, program and payer requirements. MEAT (Monitor, Evaluate, Assess, or Treat) is a review mnemonic, not a universal CMS coding rule.

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

Coder workflow notes

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What This Code Means

E06.1 is the ICD-10-CM diagnosis code for subacute thyroiditis. Inflammation of the thyroid gland that develops over weeks to months, often following a viral infection, causing temporary thyroid dysfunction. E06.1 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).

E06.1 has no mapping under the current CMS-HCC V28 community payment model. E06.1 has a separate mapping under the Part D RxHCC model (HCC 44 (Thyroid Disorders)); the applicable result needs member context. Do not assign V28 risk adjustment value from this page; verify the applicable model and payment year before using this code for risk adjustment.

Document the timeline of symptom onset to distinguish from acute thyroiditis (E06.0) or chronic forms.

HCC Buddy maintains structured V28 and V24 mapping, source-labeled coefficient references, and MEAT documentation criteria for E06.1 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•Document the timeline of symptom onset to distinguish from acute thyroiditis (E06.0) or chronic forms
•Note any preceding viral illness or upper respiratory infection in the medical record

Clinical Significance

Subacute thyroiditis (de Quervain thyroiditis) is a self-limited inflammatory condition typically following a viral upper respiratory infection, presenting with painful thyroid enlargement, fever, and a characteristic triphasic clinical course of thyrotoxicosis, hypothyroidism, and recovery. The condition is distinguished from other thyroid disorders by markedly elevated ESR and low radioactive iodine uptake during the thyrotoxic phase. Most patients recover full thyroid function within 6-12 months.

Documentation Requirements

✓Document the temporal relationship to antecedent viral illness, thyroid tenderness and enlargement on examination, laboratory findings (elevated ESR, thyroid function tests), and the current phase of the triphasic course (thyrotoxic, hypothyroid, or recovery).
✓Record treatment with NSAIDs or corticosteroids if applicable.