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ICD-10/Q66.90

Q66.90 ICD-10-CM Code: Congenital deformity of feet, unspecified, unspecified foot

Billing Status: YES. This is a valid, specific, and billable ICD-10-CM reference.

Inpatient Payment Groups (MS-DRG)

MS-DRGs this diagnosis helps define, as principal or secondary, per the CMS ICD-10-CM/PCS MS-DRG Definitions Manual v43.0, Appendix B.

  • MS-DRG 564 — OTHER MUSCULOSKELETAL SYSTEM AND CONNECTIVE TISSUE DIAGNOSES WITH MCC (MDC 08)
  • MS-DRG 565 — OTHER MUSCULOSKELETAL SYSTEM AND CONNECTIVE TISSUE DIAGNOSES WITH CC (MDC 08)
  • MS-DRG 566 — OTHER MUSCULOSKELETAL SYSTEM AND CONNECTIVE TISSUE DIAGNOSES WITHOUT CC/MCC (MDC 08)

A diagnosis appearing in a group's logic does not by itself determine the DRG assigned to a stay; the grouper uses the full claim.

Official Registry Overview & Definition

Congenital deformity of feet, unspecified, unspecified foot is a billable ICD-10-CM diagnosis code (Q66.90).

Official Tabular Instructional Notes

Sequencing, inclusion, and exclusion notes published for Q66.90 in the official ICD-10-CM tabular list.

Excludes1 — Not Coded Here

Conditions generally not reported together with this code (Excludes1) -- an error unless the two conditions are documented as unrelated to each other (ICD-10-CM Official Guidelines, Section I.A.12.a).

Change history

  • FY2020 — 2019-10-01
    Added to the code set
    Congenital deformity of feet, unspecified, unspecified foot
    FY2020 changes

Verify Before Coding

  • Billable — reportable as written.

From the code registry, the Medicare Code Editor, and the MS-DRG Definitions Manual. Check it against a full claim.

Referenced by Other Codes

Clinical classification (AHRQ CCSR):MAL008 — Musculoskeletal congenital conditions (default).

Clinical Classifications Software Refined (CCSR) for ICD-10-CM Diagnoses. Healthcare Cost and Utilization Project (HCUP), Agency for Healthcare Research and Quality.

Potential MS-DRG Relationships (FY2026)

Not on the CMS CC/MCC list — as a secondary diagnosis this code does not change MS-DRG severity.

Named in the grouper logic of 3 MS-DRGs: DRG 564 (MDC 08), DRG 565 (MDC 08), DRG 566 (MDC 08).

From the CMS MS-DRG Definitions Manual (Appendices B and C). Actual DRG assignment depends on the complete claim.

Official ICD-10-CM tabular notes on other codes that name Q66.90 or its code family.

1 Excludes1 notes: M20 (via Q66.-).

Nearest Codes in This Family

Official ICD-10-CM classifications closest to Q66.90 in its code family, with their registry titles.

  • Q66.70 — Congenital pes cavus, unspecified foot
  • Q66.71 — Congenital pes cavus, right foot
  • Q66.72 — Congenital pes cavus, left foot
  • Q66.8 — Other congenital deformities of feet
  • Q66.80 — Congenital vertical talus deformity, unspecified foot
  • Q66.81 — Congenital vertical talus deformity, right foot
  • Q66.82 — Congenital vertical talus deformity, left foot
  • Q66.89 — Other specified congenital deformities of feet
  • Q66.9 — Congenital deformity of feet, unspecified
  • Q66.91 — Congenital deformity of feet, unspecified, right foot

View all codes in the Q66 family