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ICD-10-CM 2027

ICD-10 code for fibrous chronic thyroiditis

E06.5

Other chronic thyroiditis

✓ Billable / specific

From the official ICD-10-CM alphabetic index entry “Thyroiditis › fibrous (chronic)”. Page updated September 29, 2026.

About coding fibrous chronic thyroiditis

The ICD-10-CM code for fibrous chronic thyroiditis is E06.5 (Other chronic thyroiditis).

Within E06, choose E06.5 (Other chronic thyroiditis) only when documentation doesn't support a more specific option: acute thyroiditis (E06.0), subacute thyroiditis (E06.1), chronic thyroiditis with transient thyrotoxicosis (E06.2), autoimmune thyroiditis (E06.3), drug-induced thyroiditis (E06.4) and unspecified (E06.9).

It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.

In MS-DRG v44.0, it is part of the grouping logic for DRG 011 (Tracheostomy for Face, Mouth and Neck Diagnoses or Laryngectomy with MCC, relative weight 5.6154), DRG 012 (Tracheostomy for Face, Mouth and Neck Diagnoses or Laryngectomy with CC, relative weight 4.381), DRG 013 (Tracheostomy for Face, Mouth and Neck Diagnoses or Laryngectomy without CC/MCC, relative weight 2.7307), DRG 643 (Endocrine Disorders with MCC, relative weight 1.6139), DRG 644 (Endocrine Disorders with CC, relative weight 1.0044) and DRG 645 (Endocrine Disorders without CC/MCC, relative weight 0.7459), in Pre-MDC and MDC 10 (Endocrine, Nutritional and Metabolic Diseases and Disorders), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.

Common questions about fibrous chronic thyroiditis ICD-10 codes

What is the ICD-10 code for fibrous chronic thyroiditis?

E06.5 — Other chronic thyroiditis.

Is E06.5 billable?

Yes. E06.5 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).

Can E06.5 be used as a principal diagnosis?

Yes. The Medicare Code Editor doesn't restrict E06.5 as a principal diagnosis.

Is E06.5 a CC or MCC?

No. E06.5 is neither a CC nor an MCC under MS-DRG v44.0.