T87.40
BillableInfection of amputation stump, unspecified extremity
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is T87.40 an HCC code?
Yes. T87.40 maps to Amputation Status, Lower Limb/Amputation Complications under the CMS-HCC V28 risk adjustment model (and Amputation Status, Lower Limb/Amputation Complications under V24).
HCC Category Mapping
RAF weights shown are the community, non-dual, aged base weights from the CMS risk adjustment model file. 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.
MEAT Criteria for T87.40
For T87.40 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 T87.40 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
T87.40 is the ICD-10-CM diagnosis code for infection of amputation stump, unspecified extremity. A bacterial or fungal infection occurring at an amputation site when the specific limb location is not documented or specified. T87.40 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 CMS-HCC V28 risk adjustment model, T87.40 maps to Amputation Status, Lower Limb/Amputation Complications (HCC 409) with a community, non-dual, aged base RAF weight of 0.350. The V24 model used during the PY2024–PY2025 transition mapped T87.40 the same way and at the same RAF weight. 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 only when the specific extremity cannot be determined; otherwise use more specific codes T87.41-T87.44. Because T87.40 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 T87.40 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
Clinical Significance
Infection of amputation stump represents a serious post-surgical complication requiring immediate antibiotic therapy and potential surgical intervention. This diagnosis indicates poor wound healing and increased risk of sepsis or need for revision amputation.
Documentation Requirements
- ✓Documentation of infection at amputation stump site
- ✓Clinical signs of infection (erythema, warmth, purulent drainage)
- ✓Laboratory evidence supporting infection (elevated WBC, cultures)
- ✓Specific organism identification when available
- ✓Antibiotic therapy prescribed or administered
- ✓Assessment of infection severity and extent
- ✓Treatment response documentation
- ✓Risk factors contributing to infection
Commonly Confused Codes
- •T87.41-T87.44 — Site-specific infection codes when extremity is documented
- •L03.9 — Cellulitis unspecified vs specific amputation stump infection
- •T81.4 — Infection following procedure, not elsewhere classified
- •Z87.891 — Personal history of nicotine dependence (may be risk factor)
- •T87.89 — Other amputation complications vs specific infection