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T86.8422 ICD-10-CM Code: Corneal transplant infection, left eye

T86.8422 is not a CMS-HCC payment code. MEAT criteria · RAF calculator · HCC coding software

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FY 2026 Apr update / Injury, poisoning and certain other consequences of external causes (S00-T88) / Complications of surgical and medical care, not elsewhere classified (T80-T88)

T86.8422

Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidance

Corneal transplant infection, left eye

An infection has developed in the cornea transplant of the left eye.

Buddy the Bee presenting code insight

Buddy Insight

Corneal transplant infection in the left eye represents a vision-threatening complication requiring immediate ophthalmologic intervention.

CMS-HCC V28

N/A

—

Not mapped

CMS-HCC V24

HCC 176

RAF 0.582

ACA/HHS

N/A

—

Not mapped

ESRD/PACE

HCC 176

RAF 0.000

RXHCC

N/A

—

Not mapped

Code Book Path

Official
T86.84Complications of corneal transplant
T86.842Corneal transplant infection
T86.8422Corneal transplant infection, left eye

Inclusion Terms

Official

ICD-10-CM does not list inclusion terms for T86.8422 in this effective period.

Excludes 2

Official

ICD-10-CM does not list Excludes 2 notes for T86.8422 in this effective period.

Related Child Codes

Official
T86.8421Corneal transplant infection, right eye
T86.8423Corneal transplant infection, bilateral
T86.8429Corneal transplant infection, unspecified eye

Includes

Official

ICD-10-CM does not list Includes notes for T86.8422 in this effective period.

Excludes 1

Official

ICD-10-CM does not list Excludes 1 notes for T86.8422 in this effective period.

Code First

Official

ICD-10-CM does not list Code First sequencing instructions for T86.8422 in this effective period.

Use Additional

Official
  • code to specify infection

Code Also

Official

ICD-10-CM does not list Code Also instructions for T86.8422 in this effective period.

Buddy Documentation Tip

HCC Buddy guidance
Documentation of corneal transplant procedure in left eye
Clinical signs of infection (pain, photophobia, decreased vision, discharge)
Slit-lamp examination findings demonstrating infection
Microbiologic studies or culture results if obtained

MEAT Support

HCC Buddy guidance
Documentation of corneal transplant procedure in left eye
Clinical signs of infection (pain, photophobia, decreased vision, discharge)
Slit-lamp examination findings demonstrating infection
Microbiologic studies or culture results if obtained

Audit Caution

HCC Buddy guidance
Laterality errors or omissions in documentation
Using non-specific eye infection codes
Not linking infection to previous transplant procedure
Failing to document transplant history adequately

Common Mistakes

HCC Buddy guidance
T86.8421 — corneal transplant infection, right eye (left vs right eye)
H16.9 — keratitis unspecified (transplant vs non-transplant related)
T86.8429 — corneal transplant infection, unspecified eye (specified vs unspecified laterality)
H57.9 — unspecified disorder of eye and adnexa (specific infection vs general disorder)

Current with CMS: FY2026 ICD-10-CM Apr 1 update (effective Apr 1 – Sep 30, 2026) · CMS-HCC V28, 100% phased in for payment year 2026. FY2027 code set already staged for October 1, 2026. How HCC Buddy stays current →

Is T86.8422 an HCC code?

Yes. T86.8422 maps to Complications of Specified Implanted Device or Graft under the V24 model but is not retained in V28.

Code
T86.8422
Description
Corneal transplant infection, left eye
HCC (V28)
No CMS-HCC V28 mapping
RAF
—
Billable
Yes
Payment year
2026

HCC Category Mapping

V24HCC 176, Complications of Specified Implanted Device or Graft
0.582
ESRDHCC 176, Complications of Specified Implanted Device or Graft
0.000

Each model's RAF is its CMS base weight for that model's standard population, so weights are not directly comparable across models: CMS-HCC V28 and V24 use Community, Non-Dual, Aged; ESRD uses the dialysis continuing-enrollee model; RxHCC is the Part D continuing-enrollee, non-low-income, aged weight (a larger scale than CMS-HCC). ACA/HHS has no single weight — it varies by metal level. Actual per-patient RAF contribution depends on member segment, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains in use during the transition and for historical data.

Work T86.8422 in the Code Book — tabular path, V28 RAF, and MEAT checklist →

MEAT Criteria for T86.8422

For T86.8422 to count as a valid HCC diagnosis in a given encounter, the provider's documentation must show MEAT: Monitor, Evaluate, Assess, or Treat. A diagnosis from a prior year does not carry forward automatically, it has to be re-documented and supported each calendar year.

  • MMonitor: signs, symptoms, disease progression, or lab trending documented in the note
  • EEvaluate: test results, medication response, or physical findings reviewed by the provider
  • AAssess: explicit mention in the assessment or plan with acknowledgment of status
  • TTreat: medication, referral, procedure, therapy, or counseling tied to the diagnosis

Only one of M/E/A/T is required to support the code, but the documentation must be specific enough to show that the provider actually addressed T86.8422 during that encounter, not just copy-forwarded from a problem list.

Coder workflow notes

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What This Code Means

T86.8422 is the ICD-10-CM diagnosis code for corneal transplant infection, left eye. An infection has developed in the cornea transplant of the left eye. T86.8422 sits in the ICD-10-CM chapter for injury, poisoning and certain other consequences of external causes (s00-t88), within the section covering complications of surgical and medical care, not elsewhere classified (t80-t88).

Under the older CMS-HCC V24 model, T86.8422 maps to Complications of Specified Implanted Device or Graft (HCC 176) with a community, non-dual, aged base RAF weight of 0.582. V28 is the CMS-HCC risk adjustment model that reached 100% phase-in for payment year 2026, replacing V24 which was used during the PY2024–PY2025 transition.

Use this code when infection is documented as a complication of corneal transplant in the left eye. Because T86.8422 maps to a payment HCC, the provider's documentation must satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) for the encounter to count toward the patient's Medicare Advantage risk adjustment score. When documentation is ambiguous, coders should issue a provider query rather than assume the highest-specificity variant.

HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for T86.8422 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

  • •Use this code when infection is documented as a complication of corneal transplant in the left eye
  • •Document the causative organism if available to support medical necessity and treatment decisions

Clinical Significance

Corneal transplant infection in the left eye represents a vision-threatening complication requiring immediate ophthalmologic intervention. Prompt diagnosis and treatment are essential to prevent graft rejection, scarring, and permanent vision loss.

Documentation Requirements

  • ✓Documentation of corneal transplant procedure in left eye
  • ✓Clinical signs of infection (pain, photophobia, decreased vision, discharge)
  • ✓Slit-lamp examination findings demonstrating infection
  • ✓Microbiologic studies or culture results if obtained
  • ✓Visual acuity assessment and any changes from baseline
  • ✓Antimicrobial therapy initiation and response
  • ✓Clear specification of left eye involvement
  • ✓Ophthalmologist assessment confirming transplant-related infection

Commonly Confused Codes

  • •T86.8421: corneal transplant infection, right eye (left vs right eye)
  • •H16.9: keratitis unspecified (transplant vs non-transplant related)
  • •T86.8429: corneal transplant infection, unspecified eye (specified vs unspecified laterality)
  • •H57.9: unspecified disorder of eye and adnexa (specific infection vs general disorder)
  • •Z94.7: corneal transplant status (active infection vs stable status)

Child Codes

T86.8421Corneal transplant infection, right eye
T86.8422Corneal transplant infection, left eye
T86.8423Corneal transplant infection, bilateral
T86.8429Corneal transplant infection, unspecified eye

Code Hierarchy

└T86Complications of transplanted organs and tissue└T86.8Complications of other transplanted organs and tissues└T86.84Complications of corneal transplant└T86.842Corneal transplant infection└T86.8422Corneal transplant infection, left eye
└T86.8422Corneal transplant infection, left eye

T86.8422 code history

Code setChange
FY2021 (effective Oct 1, 2020)Added to the code set

Source: official CMS ICD-10-CM order and addenda files, FY2016 through FY2027.

Because T86.8422 maps to a payment HCC, the documentation must also satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) for the encounter to count toward the patient's risk adjustment score.

More on T86.8422

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