Z89.429
BillableAcquired absence of other toe(s), unspecified side
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is Z89.429 an HCC code?
Yes. Z89.429 maps to Amputation Status, Lower Limb/Amputation Complications under the V24 model but is not retained in V28.
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 Z89.429
For Z89.429 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 Z89.429 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
Z89.429 is the ICD-10-CM diagnosis code for acquired absence of other toe(s), unspecified side. A person is missing one or more toes on an unspecified foot due to amputation, injury, or surgical removal that occurred after birth. Z89.429 sits in the ICD-10-CM chapter for factors influencing health status and contact with health services (z00-z99), within the section covering persons with potential health hazards related to family and personal history and certain conditions influencing health status (z77-z99).
Under the older CMS-HCC V24 model, Z89.429 maps to Amputation Status, Lower Limb/Amputation Complications (HCC 189) with a community, non-dual, aged base RAF weight of 0.350. 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.
This code is used when the specific side (left or right) of the foot is not documented; query the provider if laterality can be determined for more specificity. Because Z89.429 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 Z89.429 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •This code is used when the specific side (left or right) of the foot is not documented; query the provider if laterality can be determined for more specificity.
- •Verify whether this is a partial foot amputation (toes only) versus a complete foot amputation, as different codes apply.
Clinical Significance
Acquired absence of unspecified toes represents lower extremity amputation with functional impact when laterality or specific toe involvement cannot be determined. This indicates significant underlying pathology requiring ongoing management despite incomplete documentation specificity.
Documentation Requirements
- ✓Acquired nature of toe absence documented
- ✓Reason for unspecified laterality explained
- ✓Exclusion of great toe if not involved
- ✓Underlying cause or etiology noted
- ✓Functional status and mobility assessment
- ✓Current adaptive equipment use
- ✓Rehabilitation services provided
- ✓Prevention strategies for remaining tissue