Z89.431

🧬 ICD-10-CM Z89.431 — Acquired Absence Of Right Foot

Billable Code Confirmed

ICD-10-CM Z89.431 is a valid, billable 6-character ICD-10-CM code for FY2026. The Z89 category defines the acquired absence of a limb, the 4 specifies the toe/foot/ankle region, the 3 zeroes in on the foot specifically, and the 1 indicates the right side. No additional characters are required.

Non-Billable Parent Codes — Never Submit These

• ❌ Z89.4 — 4-character header — Lacks specificity regarding which part of the foot/ankle is missing.
• ❌ Z89.43 — 5-character header — Lacks specificity regarding laterality (right, left, or bilateral).

Always submit Z89.431 (all 6 characters) when a patient has a documented history of surgical or traumatic amputation of the right foot.

Clinical Context: Acquired vs. Congenital

ICD-10 CM Z89.431 captures a limb absence that occurred after birth due to trauma, infection, vascular disease, or surgery. It must not be used for patients born without a right foot (congenital agenesis), which requires a code from the Q72 block.

Code Classification

ICD-10 CM Diagnosis Code — wRVU, assistant payable, and global period fields are not applicable; direct reader to CPT Procedural Crosswalk and ICD-10-PCS Crosswalk sections.

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🔍 Code Description

ICD-10 CM Z89.431 classifies acquired absence of right foot. This code represents a patient’s status post-amputation of the right foot. It is a “status” Z-code, meaning it indicates a condition that is a continuing state influencing the patient’s health, rather than an active acute disease.

Clinically, a foot amputation (such as a Syme amputation or transmetatarsal amputation) significantly alters the patient’s biomechanics. These patients require specialized footwear, custom prosthetics, and ongoing physical medicine support. Furthermore, in patients whose amputation was secondary to peripheral artery disease (PAD) or diabetes, the presence of this code signals a high risk for ulceration or amputation of the remaining contralateral limb.

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🌳 Code Tree / Hierarchy

Z89 Acquired absence of limb ❌ Non-billable
│
├── Z89.4 Acquired absence of toe(s), foot, and ankle ❌ Non-billable
│ │
│ ├── Z89.43 Acquired absence of foot ❌ Non-billable
│ │ │
│ │ ├── Z89.431 Acquired absence of right foot ◀ THIS CODE ✅ Billable
│ │ ├── Z89.432 Acquired absence of left foot ✅ Billable
│ │ └── Z89.439 Acquired absence of unspecified foot ✅ Billable
│ │
│ └── Z89.44 Acquired absence of ankle ✅ Billable
│
└── Z89.5 Acquired absence of knee ✅ Billable

Annual Capture for Risk Adjustment

Status codes like Z89.431 do not “expire.” Because this condition permanently elevates the patient’s risk profile and resource needs, it must be documented by a provider and coded every single calendar year to satisfy requirements.

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✅ Includes

The following clinical terms and scenarios map to Z89.431 when documented:

• Status post right foot amputation

• History of right foot amputation

• Acquired absence of right foot

• Traumatic loss of right foot (historical/healed)

• S/P right Syme amputation (if restricted to foot level)

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❌ Excludes

Excludes 1 — Cannot Be Coded Simultaneously with Z89.431

Code	Description	Note
Q72.31	Congenital absence of right foot and toe(s)	Mutually exclusive. A foot cannot be simultaneously absent due to a congenital birth defect and an acquired surgical/traumatic amputation.

Excludes 1 Violation Risk

Never assign an acquired absence Z-code for a patient whose limb deficiency was present at birth. Even if the patient is 80 years old, a birth defect remains a congenital Q-code for their entire life.

Excludes 2 — May Be Coded in Addition if Separately Present

Code	Description	Note
Z89.412	Acquired absence of left great toe	It is completely appropriate to code multiple Z89 codes if the patient has distinct amputations on different limbs or different parts of the contralateral limb.

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📋 Clinical Overview

Phenotype Distinction: Lower Extremity Amputation Levels

Differentiating the anatomical level of the amputation is critical, as it changes the specific Z-code and dictates the type of prosthetic device required.

Feature	Z89.431 — Absence of Foot	Z89.441 — Absence of Ankle	Z89.511 — Absence of Leg below Knee
Affected Anatomy	Tarsals, metatarsals, phalanges	Through the ankle joint	Tibia/Fibula shaft
Common Procedure	Transmetatarsal / Chopart	Syme Amputation	Below-Knee Amputation (BKA)
Prosthetic Type	Partial foot prosthesis / Shoe insert	Syme prosthesis	BKA Socket and Pylon

CDI Query Trigger — "Lower Extremity Amputation"

If the provider’s note simply lists “Status post right lower extremity amputation” in the past medical history, it is too vague. A query should be sent asking the provider to specify the level (e.g., foot, below knee, above knee) to ensure the highest degree of specificity and proper HCC assignment.

Common Diagnoses / Clinical Indications

While Z89.431 is a status code, it frequently accompanies chronic systemic conditions that led to the amputation. Look for and code these concurrently if actively managed:

• E11.52: Type 2 diabetes mellitus with diabetic peripheral angiopathy with gangrene

• I70.261: Atherosclerosis of native arteries of extremities with gangrene, right leg

• L97.519: Non-pressure chronic ulcer of other part of right foot

Coding Manifestations

Always code the documented systemic diseases that coexist with the amputation status to fully capture the patient’s complexity:

• E11.69 — Type 2 diabetes mellitus with other specified complication

• Z99.3 — Dependence on wheelchair (if applicable due to the amputation)

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💰 HCC Risk Adjustment (CMS-HCC v28)

Field	Detail
CMS-HCC Model Version	v28 (2024-2025 Implementation)
HCC Assignment	✅ Mapped — HCC 189
HCC Category	HCC 189 — Amputation Status, Lower Limb/Amputation Complications
RAF Coefficient	~0.50 - 0.70 (varies by demographic/status)

Z89.431 maps directly to an HCC and contributes to the RAF score.

Capture Annually

HCC 189 must be captured every single calendar year. Providers must document the absence of the foot in their assessment and plan (e.g., “Right foot amputation: stable, continue current prosthetic use”) during a face-to-face encounter to validate the code for that year’s risk adjustment cycle.

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🏥 DRG Assignment

MDC 23 — Factors Influencing Health Status and Other Contacts with Health Services

DRG	Title	Est. Relative Weight*
DRG 951	Other Factors Influencing Health Status	~0.65

Approximate. Verify against IPPS FY2026 Final Rule tables.

Sequencing and Complications

Z89.431 is overwhelmingly used as a secondary diagnosis on inpatient claims. It provides vital context for nursing care and physical therapy needs during the stay but does not elevate the DRG weight as a CC or MCC.

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🔗 Related ICD-10-CM Codes

Laterality Variants

Code	Description
Z89.431	Acquired absence of right foot ← This Code
Z89.432	Acquired absence of left foot
Z89.439	Acquired absence of unspecified foot

Anatomic Site Variants

Code	Description
Z89.411	Acquired absence of right great toe
Z89.441	Acquired absence of right ankle
Z89.511	Acquired absence of right leg below knee

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🛠️ Commonly Associated CPT Codes (PM&R / Outpatient)

Outpatient and Profee Setting Context

In the physical medicine, podiatry, or primary care clinic, Z89.431 is used to justify the medical necessity for prosthetic fittings, adjustments, and gait training therapies.

CPT Code	Description	Profee Coding Notes (Modifier 26)
99213/99214	Office visit, established patient	Used for ongoing evaluation of the residual limb and prosthetic function.
97116	Therapeutic procedure, 15 mins; gait training	Billed by PTs training the patient to walk safely with the partial foot prosthesis.
L5000-L5999	Lower Extremity Prosthetics (HCPCS)	Billed by the prosthetist/DME provider for the physical device itself.
97761	Prosthetic training, upper and/or lower extremity	Initial 15 minutes of training the patient to use the device.

NCCI Bundling Considerations

• 97116 (Gait training) billed on the same day as 97761 (Prosthetic training). Depending on payer rules, these may be subject to NCCI edits. If distinct 15-minute blocks of time are spent on each separate activity, Modifier -59 (or an appropriate X- modifier) must be appended to indicate separate and distinct services.

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🔬 ICD-10-PCS Crosswalk (Inpatient Procedures)

When Z89.431 is an inpatient diagnosis, these PCS codes are relevant for associated inpatient rehabilitation interventions.

PCS Section	Body System	Root Operation	Clinical Application
F (Physical Rehab)	0 (Rehabilitation)	D (Fitting)	Fitting the patient for a new lower extremity device during an inpatient rehab stay: F0DZ8UZ (Fitting of Prosthesis, Right Lower Extremity).

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💊 Coding Scenarios and Examples

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Scenario 1 — Outpatient PM&R: Prosthetic Evaluation

Clinical Vignette: A 62-year-old male with a history of right transmetatarsal amputation secondary to diabetic vascular disease presents to the physical medicine clinic. He reports his current shoe insert prosthesis is rubbing against the residual limb, causing mild erythema. The physician evaluates the stump, notes no open ulceration, and writes an order for the prosthetist to adjust the fit.

CPT / HCPCS (Profee):

• 99213 — Office or other outpatient visit, established patient, low MDM

ICD-10-CM Diagnoses:

• Z89.431 — Acquired absence of right foot (Primary diagnosis for the encounter, explaining the need for the prosthetic adjustment).

• E11.51 — Type 2 diabetes mellitus with diabetic peripheral angiopathy without gangrene (Underlying condition requiring continued monitoring).

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Scenario 2 — Inpatient Hospitalization: Secondary Diagnosis

Clinical Vignette: A 70-year-old female is admitted with a severe soft tissue infection of her left heel. She has a documented history of a right foot amputation five years ago. During the admission, she requires IV antibiotics and a surgical debridement of the left heel. Physical therapy is consulted to assist with bed-to-chair transfers, noting her mobility is significantly impaired due to the combination of the left foot wound and the absent right foot.

Principal Diagnosis:

• L03.116 — Cellulitis of left lower limb (Reason for admission)

Secondary Diagnoses:

• Z89.431 — Acquired absence of right foot (Crucial secondary diagnosis that captures her baseline mobility deficit and justifies the intense physical therapy interventions).

MS-DRG Assignment: Groups to DRG 602 or 603 (Cellulitis with/without MCC). While Z89.431 does not increase the DRG weight, it ensures accurate severity data and HCC capture.

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Scenario 3 — CDI Query: Clarifying Vague History

Clinical Vignette: A patient is admitted for pneumonia. The provider’s history and physical (H&P) notes under Past Medical History: “Amputee - right leg.” The physical exam states: “Missing right foot, stump is well-healed.”

Action / Outcome:

“Amputee - right leg” is a vague historical statement. Based solely on the problem list, a coder might select Z89.511 (Absence of right leg below knee) or Z89.9 (Absence of unspecified limb). However, the physical exam specifies it is only the foot. A clinical validation query should be sent to the provider to confirm the exact anatomical level of the amputation for the official final diagnosis list.

Query Response: Provider updates the discharge summary to confirm: “Status post right foot amputation.”

Corrected ICD-10-CM Coding:

• Z89.431 — Acquired absence of right foot (Accurately reflects the specific level of absence).

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⚠️ Coding Pitfalls and Tips

	Pitfall or Tip
❌	Confusing Congenital vs. Acquired. Do not use Z89.431 for a patient who was born without a right foot. Congenital absences must be coded using the Q72 block, regardless of the patient’s current age.
❌	Missing the Underlying Cause. Do not code Z89.431 in isolation if the systemic disease that caused the amputation (like Type 2 Diabetes or Peripheral Artery Disease) is still present and actively managed. Code both to tell the complete clinical story.
✅	Capture Every Year. Status codes like Z89.431 map to HCC categories. For Medicare Advantage patients, ensure the provider documents the amputation status during a face-to-face encounter every calendar year so the complexity is captured by the payer.
✅	Check Laterality. Always verify the left/right orientation in the documentation. Applying Z89.431 (right) when the procedure was actually on the left (Z89.432) is a frequent audit failure.

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📚 Sources

1. CMS/NCHS. ICD-10-CM Official Guidelines for Coding and Reporting, FY2026. (Section I.C.21 - Z Codes).

2. CMS. 2025-2026 Medicare Advantage Risk Adjustment — CMS-HCC Model v28 ICD-10-CM Mappings.

3. CMS. IPPS Final Rule FY2026 — MS-DRG Definitions Manual v43.

4. AMA. CPT Professional Edition 2026. Medicine / Physical Medicine and Rehabilitation.