ICD code T86.810 – Lung transplant rejection

Key takeaways

T86.810 is the billable ICD-10-CM code for rejection of a transplanted lung, whether acute cellular, antibody-mediated or chronic.

Heart-lung transplant rejection is excluded from T86.81 and codes to T86.31, so T86.810 covers lung-only transplants.

Leave Z94.2 off the claim, because T86.810 already tells the payer the patient has a transplanted lung.

For CLAD due to chronic rejection, sequence T86.810 first, then J4A.-, and add J44.81 for bronchiolitis obliterans syndrome.

Code only the rejection the provider names, and query any note that mentions CLAD or BOS without a cause.

ICD-10 code T86.810 covers rejection of a lung-only transplant

ICD-10 code T86.810 identifies lung transplant rejection, an immune attack by the recipient on a donor lung. It is valid and billable for FY2027, which took effect on October 1, 2026.

The code applies to a lung transplanted on its own, single or bilateral. A combined heart-lung transplant codes to T86.31 instead, because an Excludes1 note at T86.81 keeps the two branches apart.

One more condition comes from Section I.C.19.g.3.a of the FY2027 ICD-10-CM Official Guidelines. A T86 code applies only when the complication affects the transplanted organ’s function.

What the code record shows

You can confirm each field in the CDC/NCHS ICD-10-CM browser tool. There, T86.81 shows as a header that is not billable on its own. T86.810 sits one level below it, at the sixth character.

Three forms of rejection all code to T86.810

Rejection is the recipient’s immune response against the donor lung. The International Society for Heart and Lung Transplantation (ISHLT) recognizes three broad forms. T86.810 applies to each, once the provider documents it as rejection.

• Acute cellular rejection: lymphocytic infiltrates around blood vessels on transbronchial biopsy. The ISHLT 2007 revised working formulation grades them from A0 (none) to A4 (severe). Airway inflammation is graded separately, from B0 to B2R.
• Antibody-mediated rejection: donor-specific antibodies against HLA plus compatible lung histology, with or without C4d staining. The criteria come from the 2016 ISHLT consensus report.
• Chronic rejection: usually documented as chronic lung allograft dysfunction (CLAD). The 2019 ISHLT consensus defines it as a persistent FEV1 decline of at least 20% from the post-transplant baseline.

CLAD has two main phenotypes. Bronchiolitis obliterans syndrome (BOS) is obstructive. Restrictive allograft syndrome (RAS) adds a restrictive defect with parenchymal fibrosis. Each one has its own manifestation code, which the CLAD section below walks through.

Four tabular notes shape every T86.810 claim

Notes at three levels of the tabular list flow down to T86.810. A fourth, in the Z codes, decides what stays off the claim.

• Use additional code (category T86): identifies other transplant complications. Examples are graft-versus-host disease (D89.81-), transplant-associated malignancy (C80.2) and post-transplant lymphoproliferative disorder (D47.Z1).
• Excludes1 (subcategory T86.81): complication of heart-lung transplant (T86.3-).
• Use additional code (block T80-T88): names the condition the complication caused. A drug’s adverse effect takes a T36-T50 code with fifth or sixth character 5.
• Excludes1 (category Z94): complications of transplanted organ or tissue. That note is why Z94.2 never pairs with T86.810.

Rejection, failure or infection decides the T86.81 code

The five T86.81 codes split by what the provider documents happening to the graft. Rejection is an immune process. Loss of graft function codes to T86.811, and a pathogen in the graft codes to T86.812.

Here’s a quick test. If the note says rejection, you are on T86.810. If it says failure and never mentions rejection, you are on T86.811. When a note uses both words loosely, query the provider rather than choose.

Chronic rejection and CLAD put T86.810 first

Chronic rejection needs the most care, because the note may say CLAD, BOS or RAS instead of rejection. Code-first notes on the manifestation codes settle the order.

• J4A.- Chronic lung allograft dysfunction: J4A.0 restrictive allograft syndrome, J4A.8 other and J4A.9 unspecified. The category tells you to code first T86.810 or T86.818, if applicable.
• J44.81 Bronchiolitis obliterans and bronchiolitis obliterans syndrome: carries the same code-first instruction, plus a code-also note pointing to J4A.-.
• Mixed CLAD: J4A.0 has a code-also note for J44.81, so a mixed BOS and RAS picture takes both manifestation codes.

The choice between T86.810 and T86.818 rests on the provider’s attribution. The diagram below maps the three outcomes, and Z94.2 stays off in every one.

Example: RAS two years after a bilateral transplant

A patient is two years past a bilateral lung transplant. Serial spirometry shows a sustained FEV1 drop, and CT shows new fibrosis. The pulmonologist documents “CLAD, RAS phenotype, due to chronic rejection.”

That note supports T86.810 first and J4A.0 second. Had it said only “CLAD, RAS phenotype,” the coder would query the cause before picking T86.810 or T86.818.

Sequencing puts T86.810 first and the manifestation second

Guideline I.C.19.g.3.a requires two codes for a transplant complication. The first is the T86 code. The second identifies the complication itself.

• Principal or first-listed: T86.810, when rejection is the reason for the admission or encounter.
• Manifestation: J4A.- and J44.81 for chronic rejection. Acute respiratory failure (J96.0-) also follows when the provider links it to the rejection.
• Drug effects: when an immunosuppressant side effect is being treated, add the adverse-effect code. T45.1X5- covers antineoplastic and immunosuppressive drugs.
• Other transplant complications: D89.81- for graft-versus-host disease, C80.2 for transplant-associated malignancy, and D47.Z1 for PTLD.
• No status code: leave Z94.2 off the claim. Guideline I.C.21.c.3 bars a status code when the diagnosis code already carries that information.

Some conditions only look like transplant complications. A pre-existing condition, or one that develops without affecting the graft, gets coded on its own. In those cases, leave T86.810 out.

Documentation must name the rejection and its effect on the graft

The note has to support three elements: a lung transplant, a rejection diagnosis and an effect on graft function. Coders take the diagnosis from the treating provider. A biopsy grade or a falling FEV1 alone does not support the code.

• Transplant details: a lung transplant, single or bilateral, and its date, so the record rules out a heart-lung transplant.
• Rejection type: acute cellular, antibody-mediated or chronic, stated in the provider’s own words.
• Supporting findings: the biopsy grade (for example, ISHLT A2), donor-specific antibody results, or serial spirometry against baseline FEV1.
• Effect on the graft: the hypoxemia, FEV1 decline, imaging change or symptoms that the provider links to rejection.
• CLAD phenotype: BOS, RAS or mixed, whenever chronic rejection is diagnosed, so the J4A and J44.81 codes can follow.
• Treatment plan: for example, augmented immunosuppression or plasmapheresis, which supports the medical necessity of the encounter.

How a T86.810 claim moves, and where it stalls

A transplant claim passes through five hands before it is paid. Each step has its own way of sending it back.

1. The encounter note: the provider names the rejection type and ties it to graft function. A vague note stalls the claim before coding starts.
2. Coding: the coder assigns T86.810, the manifestation codes and any adverse-effect code. A CLAD note with no stated cause goes back as a query.
3. The claim build: codes go on in sequence, with T86.810 first when rejection drives the visit. Retyped codes are where slips creep in.
4. Clearinghouse edits: format and required-field checks run before the payer sees the claim. A missing member ID or authorization number bounces it here.
5. Payer review: the payer adjudicates and may ask for records. A biopsy grade with no provider diagnosis will not hold up at this stage.

Five T86.810 mistakes that send claims back

Most T86.810 problems trace back to a mismatch between the code set and the note. A clean claim depends on catching these before submission.

Watch for one more habit, too. Coders sometimes settle for T86.819 when the note names a complication but not its type. A short query usually earns a more specific code.

Before you submit: A T86.810 claim checklist

Run these checks on every lung transplant claim before it leaves the practice.

• The record shows a lung-only transplant, not a heart-lung transplant.
• The provider names rejection and links it to graft function.
• T86.810 is first-listed when rejection drives the encounter.
• Each documented manifestation has its own code, such as J4A.-, J44.81 or J96.0-.
• Any CLAD or BOS note without a stated cause has a query answer on file.
• Z94.2 is off the claim.
• A treated immunosuppressant side effect carries its T45.1X5- code.
• Member ID and authorization fields are complete.

When a claim needs a different diagnosis code, our diagnostic codes guide lets you look it up by code or condition.

Pabau carries transplant codes from the record to the claim

Lung transplant follow-up produces a steady run of encounters, from biopsies and spirometry to infusion visits. Each claim repeats the same transplant codes in the same order, and retyping them invites slips.

Pabau, the practice management and billing platform we build, keeps ICD-10-CM codes on the patient record. It pre-fills them onto each claim, and staff can search T86.810, J4A.9 or J44.81 by code or description.

Its claims management software checks that required fields, such as membership numbers and authorization codes, are complete before sending. Claims then go out through a connected clearinghouse such as Claim.MD.

Pabau does not check code pairings or sequencing itself, so the checklist above stays with your coders. When the clearinghouse returns a rejection, your team corrects and resubmits it in one place.

Send transplant claims without rekeying codes

Pabau pre-fills claims with the diagnosis codes on the patient record. It sends them through your clearinghouse, so rejections come back to one place.

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Conclusion

T86.810 itself is rarely the problem. It is narrow and billable, and a good transplant note usually names it plainly.

Claims stall on the codes around it. So build two habits into every lung transplant encounter. Query any CLAD note that skips the cause, and strip Z94.2 before the claim goes out.

Both cost a little time up front. A one-line query takes minutes, while a returned claim costs a resubmission and a later payment.

Book a demo to see how Pabau carries transplant diagnosis codes from the patient record onto every claim.

Continue your research

Coding a graft that has stopped working? ICD-10 code T86.811: Lung transplant failure explains when failure, not rejection, is the right code.

Is the transplant a combined heart-lung graft? ICD-10 code T86.31: Heart-lung transplant rejection covers the branch that T86.81 excludes.

Need help managing insurance denials systematically? Medical billing compliance guide covers the documentation and audit-readiness practices that prevent post-payment recoupment.

Want to understand the clearinghouse process for electronic claims? How medical claims clearinghouses work explains payer routing, edit checks, and ERA processing.

Looking for the full list of standard denial reason codes? Electronic remittance advice (ERA) explained walks through CARC and RARC denial codes returned on 835 remittances.

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