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ICD-10/T21.73

T21.73 ICD-10-CM Code: Corrosion of third degree of upper back

Billing Status: NO. This is a clinician non-billable / parent hierarchy grouping in the ICD-10-CM system.

Official Registry Overview & Definition

Corrosion of third degree of upper back is a non-billable ICD-10-CM category code (T21.73). A more specific billable subcode must be selected for claims submission.

Official Tabular Instructional Notes

Sequencing, inclusion, and exclusion notes published for T21.73 in the official ICD-10-CM tabular list.

Includes

Conditions the official ICD-10-CM tabular list includes under this code.

  • burns and corrosion of hip region
  • burns and corrosions of first degree [erythema]
  • burns and corrosions of second degree [blisters][epidermal loss]
  • burns and corrosions of third degree [deep necrosis of underlying tissue] [full- thickness skin loss]

Inclusion Terms

Alternative terms the tabular list files under this code.

  • Corrosion of third degree of interscapular region

Excludes2 — Not Included Here

Conditions not covered by this code, but which may be reported alongside it when both are present.

Code First

Underlying conditions that must be sequenced before this code.

  • (T51-T65) to identify chemical and intent

Use Additional Code

Supplementary codes the tabular list directs you to add.

  • external cause code to identify place (Y92)
  • Use additional code from category T31 or T32 to identify extent of body surface involved

Change history

No changes recorded for this code — unchanged since the FY2016 baseline of the change ledger.

Verify Before Coding

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

Contextual Map

Every relationship of T21.73 in one view: hierarchy, official tabular instructions in both directions, clinical classification, risk adjustment, MS-DRG participation, index terms and change history — each edge carrying the CMS source it derives from.

Hierarchy

  • S00-T88 — Chapter 19: Injury, Poisoning and Certain Other Consequences of External Causes (S00-T88) (S00-T88) [Hierarchy]

Referenced by Excludes2 notes

  • T22 — Burn and corrosion of shoulder and upper limb, except wrist and hand [Excludes2](via T21.-): “burn and corrosion of interscapular region (T21.-)”
  • T24 — Burn and corrosion of lower limb, except ankle and foot [Excludes2](via T21.-): “burn and corrosion of hip region (T21.-)”

Index entries

  • Corrosion (injury) (acid) (caustic) (chemical) (lime) (external) (internal), back (lower), upper, third degree[Index term]

Nearest codes (40)

  • T21 — Burn and corrosion of trunk [Sibling]
  • T21.67XA — Corrosion of second degree of female genital region, initial encounter [Sibling]
  • T21.67XD — Corrosion of second degree of female genital region, subsequent encounter [Sibling]
  • T21.67XS — Corrosion of second degree of female genital region, sequela [Sibling]
  • T21.69 — Corrosion of second degree of other site of trunk [Sibling]
  • T21.69XA — Corrosion of second degree of other site of trunk, initial encounter [Sibling]
  • T21.69XD — Corrosion of second degree of other site of trunk, subsequent encounter [Sibling]
  • T21.69XS — Corrosion of second degree of other site of trunk, sequela [Sibling]
  • and 32 more

Referenced by Other Codes

Official ICD-10-CM tabular notes on other codes that name T21.73 or its code family.

2 Excludes2 notes: T22 (via T21.-), T24 (via T21.-).

Frequently Asked Questions (FAQ) & Clinical Guidance

Can T21.73 be billed directly?

No. T21.73 (Corrosion of third degree of upper back) is a non-billable ICD-10-CM category code. A more specific billable subcode must be selected based on clinical documentation.

Does T21.73 require a 7th character?

Yes. The appropriate 7th character is to be added to each code from category T21.

Nearest Codes in This Family

Official ICD-10-CM classifications closest to T21.73 in its code family, with their registry titles.

  • T21.71XS — Corrosion of third degree of chest wall, sequela
  • T21.72 — Corrosion of third degree of abdominal wall
  • T21.72XA — Corrosion of third degree of abdominal wall, initial encounter
  • T21.72XD — Corrosion of third degree of abdominal wall, subsequent encounter
  • T21.72XS — Corrosion of third degree of abdominal wall, sequela
  • T21.73XA — Corrosion of third degree of upper back, initial encounter
  • T21.73XD — Corrosion of third degree of upper back, subsequent encounter
  • T21.73XS — Corrosion of third degree of upper back, sequela
  • T21.74 — Corrosion of third degree of lower back
  • T21.74XA — Corrosion of third degree of lower back, initial encounter

View all codes in the T21 family

Indexed Clinical Terms (1)

Clinical term phrases from the official ICD-10-CM Index to Diseases and Injuries that map to this code.

  • Corrosion (injury) (acid) (caustic) (chemical) (lime) (external) (internal), back (lower), upper, third degree