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ICD-10-CM 2027 diagnosis code

D66Hereditary factor VIII deficiency

✓ Billable / specificMCC — major complication/comorbidity

D66 is a valid, billable ICD-10-CM code for hereditary factor viii deficiency. It can be reported on claims for dates of service from October 1, 2026 – September 30, 2027.

Looking up by condition? See ICD-10 code for Hemophilia, ICD-10 code for A hemophilia, ICD-10 code for Subhemophilia, ICD-10 code for Bleeder's disease.

Code unchanged since ICD-10-CM took effect on October 1, 2015. Source: official FY2027 ICD-10-CM release from CDC/NCHS and CMS. Page updated September 29, 2026. About our data

About D66

D66 is the ICD-10-CM diagnosis code for hereditary factor VIII deficiency. It belongs to block D65-D69 (coagulation defects, purpura and other hemorrhagic conditions) and chapter 3 (diseases of the blood and blood-forming organs and certain disorders involving the immune mechanism). It is billable, so it can be reported on its own for dates of service from October 1, 2026 through September 30, 2027.

Don't report D66 together with the conditions in its Excludes1 note: factor VIII deficiency with vascular defect (D68.0-).

As a secondary diagnosis it is an MCC (major complication or comorbidity), which can move an inpatient stay into the highest-paying "with MCC" MS-DRG of its family, unless the principal diagnosis excludes it.

In MS-DRG v44.0, it is part of the grouping logic for DRG 813 (Coagulation Disorders, relative weight 1.5257), in MDC 16 (Diseases and Disorders of the Blood and Blood Forming Organs and Immunological 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.

It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.

Before ICD-10, this condition was coded in ICD-9-CM as 286.0 (congenital factor VIII disorder).

Coding notes

Applicable toConditions and synonyms classified to this code
  • Classical hemophilia
  • Deficiency factor VIII (with functional defect)
  • Hemophilia NOS
  • Hemophilia A
Excludes1Not coded here — never report together with this code
  • factor VIII deficiency with vascular defect (D68.0-)

Notes that apply from higher levels

Instructions written at a parent level also apply to D66.

Broader instructions also apply from Chapter 3: Diseases of the blood and blood-forming organs and certain disorders involving the immune mechanism.

Alphabetic index entries

11 entries

Terms in the official ICD-10-CM index that lead to D66.

Codes whose notes reference D66

MS-DRG v44.0 grouping

All DRGs →

Inpatient MS-DRGs this diagnosis can group to, as the principal or a secondary diagnosis, depending on the rest of the claim.

MDC 16 · Diseases and Disorders of the Blood and Blood Forming Organs and Immunological Disorders

ICD-9-CM equivalent

Converter →
  • 286.0Congenital factor VIII disorderexact

From the CMS 2018 General Equivalence Mappings (GEMs), the final GEMs release.

Code history

  1. 2016
  2. 2017
  3. 2018
  4. 2019
  5. 2020
  6. 2021
  7. 2022
  8. 2023
  9. 2024
  10. 2025
  11. 2026
  12. 2027
  • FY2016 (effective 10/1/2015): Added (first year of ICD-10-CM)
  • No changes since FY2016.

Common questions about D66

Is D66 billable?

Yes. D66 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).

Can D66 be used as a principal diagnosis?

Yes. The Medicare Code Editor doesn't restrict D66 as a principal diagnosis.

Is D66 a CC or MCC?

D66 is an MCC (major complication or comorbidity) under MS-DRG v44.0, unless excluded by the principal diagnosis.

What DRG does D66 group to?

D66 is used in the MS-DRG v44.0 logic for MS-DRG 813 (Coagulation Disorders). Which one applies depends on whether it is the principal diagnosis and on the rest of the claim.

What is the ICD-9 code for D66?

The CMS General Equivalence Mappings map D66 to ICD-9-CM 286.0.