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C76.42 ICD-10-CM Code: Malignant neoplasm of left upper limb

C76.42 maps to CMS-HCC V28 23 (RAF 0.186). Documentation must support MEAT. MEAT criteria · RAF calculator · HCC Buddy coding tools

ICD-10-CM Code View

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FY 2026 Apr update / Neoplasms (C00-D49) / Malignant neoplasms of ill-defined, other secondary and unspecified sites (C76-C80)

C76.42

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

Malignant neoplasm of left upper limb

Cancer that has developed in the left upper arm, hand, or shoulder area.

Buddy the Bee presenting code insight

Buddy Insight

Malignant neoplasm of the left upper limb is the left-sided counterpart for ill-defined upper extremity malignancies.

CMS-HCC V28

HCC 23

RAF 0.186

CMS-HCC V24

HCC 12

RAF 0.150

ACA/HHS

HCC 12

Varies by metal level

ESRD/PACE

HCC 12

RAF 0.045

RXHCC

HCC 22

RAF 0.124

Code Book Path

Official
C76Malignant neoplasm of other and ill-defined sites
C76.4Malignant neoplasm of upper limb
C76.42Malignant neoplasm of left upper limb

Inclusion Terms

Official

ICD-10-CM does not list inclusion terms for C76.42 in this effective period.

Excludes 2

Official

ICD-10-CM does not list Excludes 2 notes for C76.42 in this effective period.

Related Child Codes

Official
C76.40Malignant neoplasm of unspecified upper limb
C76.41Malignant neoplasm of right upper limb

Includes

Official

ICD-10-CM does not list Includes notes for C76.42 in this effective period.

Excludes 1

Official

ICD-10-CM does not list Excludes 1 notes for C76.42 in this effective period.

Code First

Official

ICD-10-CM does not list Code First sequencing instructions for C76.42 in this effective period.

Use Additional

Official

ICD-10-CM does not list Use Additional Code instructions for C76.42 in this effective period.

Code Also

Official

ICD-10-CM does not list Code Also instructions for C76.42 in this effective period.

Buddy Documentation Tip

HCC Buddy guidance
Documentation confirming left upper limb malignancy
Pathology with tissue typing
Imaging documenting location and extent within the left upper extremity
Functional assessment and neurovascular status

MEAT Support

HCC Buddy guidance
Documentation confirming left upper limb malignancy
Pathology with tissue typing
Imaging documenting location and extent within the left upper extremity
Functional assessment and neurovascular status

Audit Caution

HCC Buddy guidance
Using ill-defined site code when a tissue-specific code is available
Transposing laterality
Not pursuing pathological identification of tissue of origin
Coding lymphedema-associated angiosarcoma or other specific entities under this ill-defined code

Common Mistakes

HCC Buddy guidance
C76.41 — Right upper limb: Laterality error; confirm left side
C76.40 — Unspecified upper limb: Use C76.42 when left side is documented
C40.02 — Malignant neoplasm of bones of left upper limb: Use for bone tumors
C49.12 — Connective tissue of left upper limb: Use for soft tissue sarcomas

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 C76.42 an HCC code?

Yes. C76.42 (Malignant neoplasm of left upper limb) maps to Prostate, Breast, and Other Cancers and Tumors under the CMS-HCC V28 risk adjustment model (and Breast, Prostate, and Other Cancers and Tumors under V24), with a community non-dual aged RAF of 0.186. It is billable for payment year 2026.

Coder answer: C76.42 is billable and maps to V28 HCC 23, Prostate, Breast, and Other Cancers and Tumors. Open it in the Code Book for the tabular path, RAF, and MEAT checklist.

Code
C76.42
Description
Malignant neoplasm of left upper limb
HCC (V28)
HCC 23 — Prostate, Breast, and Other Cancers and Tumors
RAF
0.186
Billable
Yes
Payment year
2026

HCC Category Mapping

V28HCC 23, Prostate, Breast, and Other Cancers and Tumors
0.186
V24HCC 12, Breast, Prostate, and Other Cancers and Tumors
0.150
ESRDHCC 12, Breast, Prostate, and Other Cancers and Tumors
0.045
RxHCCHCC 22, Cancer, Other Specified Sites
0.124

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 C76.42 in the Code Book — tabular path, V28 RAF, and MEAT checklist →

MEAT Criteria for C76.42

For C76.42 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 C76.42 during that encounter, not just copy-forwarded from a problem list.

Coder workflow notes

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What This Code Means

C76.42 is the ICD-10-CM diagnosis code for malignant neoplasm of left upper limb. Cancer that has developed in the left upper arm, hand, or shoulder area. C76.42 sits in the ICD-10-CM chapter for neoplasms (c00-d49), within the section covering malignant neoplasms of ill-defined, other secondary and unspecified sites (c76-c80).

Under the CMS-HCC V28 risk adjustment model, C76.42 maps to Prostate, Breast, and Other Cancers and Tumors (HCC 23) with a community, non-dual, aged base RAF weight of 0.186. Under the older CMS-HCC V24 model, C76.42 maps to Breast, Prostate, and Other Cancers and Tumors (HCC 12) with a community, non-dual, aged base RAF weight of 0.150. 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.

Ensure documentation clearly specifies 'left' side before assigning this code. Because C76.42 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 C76.42 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

  • •Ensure documentation clearly specifies 'left' side before assigning this code
  • •This includes malignancies of the left shoulder, upper arm, forearm, wrist, and hand

Clinical Significance

Malignant neoplasm of the left upper limb is the left-sided counterpart for ill-defined upper extremity malignancies. As with the right-sided code, the specific tissue of origin cannot be determined from available documentation. Provider query and pathology review should be pursued to assign a more tissue-specific code when possible.

Documentation Requirements

  • ✓Documentation confirming left upper limb malignancy
  • ✓Pathology with tissue typing
  • ✓Imaging documenting location and extent within the left upper extremity
  • ✓Functional assessment and neurovascular status
  • ✓Treatment plan

Commonly Confused Codes

  • •C76.41: Right upper limb: Laterality error; confirm left side
  • •C76.40: Unspecified upper limb: Use C76.42 when left side is documented
  • •C40.02: Malignant neoplasm of bones of left upper limb: Use for bone tumors
  • •C49.12: Connective tissue of left upper limb: Use for soft tissue sarcomas
  • •C43.62: Melanoma of left upper limb: Use for melanoma

Child Codes

C76.40Malignant neoplasm of unspecified upper limb
HCC 23
C76.41Malignant neoplasm of right upper limb
HCC 23
C76.42Malignant neoplasm of left upper limb
HCC 23

Code Hierarchy

└C76Malignant neoplasm of other and ill-defined sites└C76.4Malignant neoplasm of upper limb└C76.42Malignant neoplasm of left upper limb
└C76.42Malignant neoplasm of left upper limb

Because C76.42 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.

C76.42 maps to CMS-HCC V28 category 23, Prostate, Breast, and Other Cancers and Tumors. See the ICD-10 to HCC mapping hub for how the V28 crosswalk works. Because C76.42 carries a payment HCC, you can see what it adds to a RAF score and check the documentation the chart needs before it is submitted.

Work C76.42 in HCC Buddy

Open C76.42 in the Code Book for the full Index-to-Tabular path, MEAT checklist, and V28 HCC mapping, or in the Encoder to code from a keyword search. Pro includes 7 days to try everything, no card required.

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