ICD-10 Code T86.820: Skin graft (allograft) rejection

ICD-10 Code T86.820 is the billable ICD-10-CM diagnosis code for skin graft (allograft) rejection. It covers an immune-mediated response in which the host’s immune system damages a transplanted donor skin graft. The code is valid for FY2026, effective October 1, 2025.

Rejection differs from graft failure (T86.821) in mechanism. Rejection is immune-mediated, while failure follows ischemia, infection, or another non-immunologic cause. This reference covers the code hierarchy, all five siblings in the T86.82 family, documentation requirements, and the FY2026 coding notes.

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Key takeaways

ICD-10 Code T86.820 is a billable ICD-10-CM code for skin graft (allograft) rejection, and it sits under the broader T86.82 subcategory.

T86.820 covers immune-mediated rejection only, while T86.821 covers skin graft loss from non-immune causes such as ischemia or shear.

The T86.82 family carries five billable codes: T86.820, T86.821, T86.822, T86.828 and T86.829.

Documentation must show an immune mechanism through biopsy findings, immune workup results, or a clear physician attestation of rejection.

Pabau’s claims management software submits T86.820 diagnoses through Claim.MD, validates them against 4,000+ payer rules, and tracks ERA remittances.

ICD-10 Code T86.820: Definition and billable status

T86.820 is a valid, billable ICD-10-CM code for skin graft (allograft) rejection. The descriptor comes from the CMS ICD-10-CM FY2026 code set. Billable means the code is specific enough for a claim without a more granular sub-code. Coders assign it directly to a diagnosis field on a CMS-1500 form or an 837P electronic claim.

Despite the parenthetical “(allograft)(autograft)” on the parent code T86.82, T86.820 describes allograft rejection only. The sibling codes T86.821 and T86.822 carry both parentheticals in their descriptors, so the narrower wording of T86.820 is deliberate.

Autograft rejection is immunologically rare, and a record that documents it should go back to the treating physician for clarification. The WHO ICD-10 classification framework is the base that CMS extends when it builds out these transplant complication codes.

Code hierarchy: Where T86.820 sits in ICD-10-CM

T86.820 sits five levels deep in the ICD-10-CM Tabular List, from chapter down to the specific code. The ICD-10-CM code library holds the other diagnosis codes a graft case tends to need alongside it.

The parent subcategory T86.82 is itself non-billable. Coders must assign one of the five specific T86.82x codes instead. Never report T86.82 alone on a claim, because payers reject it as insufficiently specified. Use the CDC/NCHS ICD-10-CM web tool to confirm billable status for the date of service.

Clinical description: Skin graft (allograft) rejection

Allograft rejection is an immune-mediated process. The host’s T-lymphocytes recognize donor skin antigens as foreign and mount a response that damages the grafted tissue. Graft loss from ischemia or infection carries no immune component, which is why it takes a different code.

Clinically, rejection presents with erythema, edema, blistering, or loss of graft adherence at the recipient site. Biopsy findings showing lymphocytic infiltration support the diagnosis. The treating physician’s documentation must name rejection rather than failure as the mechanism.

Rejection vs. failure: The distinction that decides the code

• T86.820 (Rejection): Immune-mediated. Host immune cells attack donor tissue. Documentation should reference an immune workup, a biopsy, or a physician attestation of the rejection mechanism.
• T86.821 (Failure): Non-immune or multi-factorial graft loss. Poor vascularization, infection, mechanical shear, or patient-related factors may be involved. No immune mechanism is required.
• Overlap cases: When documentation mentions both mechanisms, query the physician to establish the primary etiology before selecting a code. A T86.820 assigned without immune-mechanism documentation is what a denials reviewer looks for first.

Documentation requirements for T86.820

The medical record must demonstrate an immune-mediated rejection event rather than another form of graft complication. Records that already carry that evidence at the point of coding move through adjudication with fewer document requests.

The following elements support T86.820 when present in the clinical record:

• Physician attestation: A clear statement from the treating or consulting physician that the graft complication is rejection rather than failure.
• Biopsy report: Histopathologic evidence of lymphocytic infiltration or other rejection-pattern findings at the graft site.
• Immune workup documentation: Laboratory or clinical evidence of immune-mediated activity, where such testing was performed.
• Clinical course description: Onset and progression of erythema, edema or sloughing at the graft site, plus the response to any immunosuppressive intervention.
• Procedure context: Documentation confirming the graft was an allograft from a donor rather than an autograft taken from the patient.
• Timeframe: Date of the original graft procedure relative to the onset of rejection symptoms, which establishes the complication relationship.

The graft procedure itself is billed separately from the complication. A skin substitute graft applied to the trunk, arms or legs is reported with CPT 15271. The two encounter dates should line up in the record.

A record that documents only “graft complication” without naming rejection as the mechanism does not support this code. T86.829 is the more defensible assignment in that situation, though a physician query to clarify is always preferable.

Sibling codes in the T86.82 family

T86.820 belongs to the T86.82x family, which covers complications of skin graft (allograft)(autograft). The family carries five billable codes, and each one captures a distinct complication type. Selecting the wrong sibling is the most common error in this subcategory.

The diagram below condenses the family into the one question a coder puts to the record: what does the note say happened to the graft?

T86.821: Skin graft failure

T86.821 codes for skin graft failure, a clinically distinct outcome from rejection. Failure occurs when the graft never establishes a viable blood supply, or when infection, mechanical disruption or metabolic factors cause graft loss.

The documentation signal is the absence of immune-mechanism language. A note reading “graft failed to take” or “graft necrosis secondary to infection” supports T86.821.

T86.822: Skin graft infection

T86.822 covers infection of a skin graft, and its descriptor spans both allografts and autografts. Use it when the physician documents infection at the graft site as the complication being treated.

Infection can also precipitate graft loss, so read the note for the mechanism the physician treats as primary. Where infection and rejection are both documented, a query settles which one the claim leads with.

T86.828: Other complications of skin graft

T86.828 is the residual category within the T86.82x family. Use it when the documented complication is specific but falls outside rejection, failure and infection.

Contracture formation, graft-site fibrosis and pigmentation changes recorded by the physician may map here. T86.828 should never serve as a default when the complication type is unknown, because T86.829 is the accurate choice there.

Coding notes and applicable-to guidance

The ICD-10-CM Tabular List includes official notes that govern how T86.820 is used. Verify them against the AAPC ICD-10-CM lookup or the CDC/NCHS tool for the applicable fiscal year, since notes are revised annually.

These are the notes that apply to T86.820 and to the broader T86 category:

• Applicable To (T86.820): Rejection of skin graft. A record documenting “rejection of skin graft” therefore maps to T86.820.
• Use additional code (T86 category): Assign additional codes to identify related transplant complications where they are documented. Examples include graft-versus-host disease (D89.81-), transplant-associated malignancy (C80.2) and post-transplant lymphoproliferative disorder (D47.Z1).
• Excludes2 (T86.82): Complication of artificial skin graft, which is coded to T85.693. An Excludes2 note means the two conditions are separate, so both codes may be reported when both are documented.
• 7th character: No 7th character extension is required for T86.820. This code is complete at the 6-character level.

When to query the physician

The most common decision point for T86.820 is telling it apart from adjacent codes in the T86 transplant complication family. Plastic surgery, burn and wound care records often describe a graft complication without naming the mechanism at all.

A structured query does not need to be complex. Ask the physician to confirm whether the complication is rejection, failure, infection, or another type. AHIMA’s query guidelines support this approach, and most EHR systems allow templated queries to be attached to the encounter note.

Finding the code in the Alphabetic Index

The ICD-10-CM Alphabetic Index offers several pathways to T86.820. Coders who start in the Index and then verify in the Tabular List follow the sequencing process the official guidelines set out.

Common Alphabetic Index pathways to T86.820 include:

• Rejection > graft > skin (allograft): T86.820
• Complication(s) > transplant > skin > rejection: T86.820
• Graft > skin > rejection: T86.820
• Skin graft > complication > rejection: T86.820

Always verify the index-derived code against the Tabular List before assigning. The Tabular List is the final authority and may carry notes, exclusions or instructions the Alphabetic Index does not show.

How Pabau handles skin graft complication claims

Most practices settle the rejection-versus-failure question in the chart, then rekey the diagnosis into a separate billing tool or a clearinghouse portal. The decision effectively gets made twice, and the two records can drift apart before the claim is transmitted.

Practice management software like Pabau keeps the diagnosis attached to the encounter it came from. Pabau’s claims software for practices submits T86.820 electronically through Claim.MD, our US clearinghouse partner. Claims are validated against rules from 4,000+ US payers, including Medicare and Medicaid, before they leave the practice.

Electronic remittance advice returns in the standard 835 format and posts against the original claim. A coder can see how each T86.820 line was adjudicated without opening a payer portal. Where denials repeat, the cause is usually thin documentation of the immune mechanism. That pattern shows up in the same record the note was written in.

Simplify skin graft coding and claims submission

Pabau integrates with Claim.MD to submit T86.820 diagnoses electronically, validate claims against 4,000+ US payer rules, and receive ERA remittances in your workflow. See how plastic surgery and wound care practices handle graft complication billing.

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Conclusion

T86.820 turns on one word in the note. Where the physician names an immune mechanism, the code holds up under review. Where the note says only that the graft was lost, a query is the cheaper move.

The five T86.82x codes leave little room for a judgment call, so the work sits upstream of coding. Build the rejection-versus-failure question into the post-operative follow-up template and the claim writes itself. Skip it, and the answer has to be chased weeks later from a physician who has moved on.

Book a demo to see how Pabau keeps the diagnosis, the supporting documentation and the claim for a graft complication in one record.

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