C56.2 maps to CMS-HCC V28 22. A source-labeled RAF reference is available. Confirm the documented diagnosis and applicable coding requirements. MEAT criteria · RAF Calculator · HCC Buddy coding tools

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Code lookupC56.2

Effective periodFY2026 Apr Update (Apr 1-Sep 30)

FY 2026 Apr update / Neoplasms (C00-D49) / Malignant neoplasms of female genital organs (C51-C58)

C56.2

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

Malignant neoplasm of left ovary

This code represents cancer that has started in the left ovary, one of the two female reproductive organs that produce eggs. It is used when a malignant (cancerous) tumor is confirmed to be located specifically on the left side.

Buddy Insight

Malignant neoplasm of the left ovary carries the same clinical gravity as right-sided disease.

Overview Risk Models Code Book Documentation Audit Notes Edition comparison

CMS-HCC V28

Mapped

HCC 22

Bladder, Colorectal, and Othe...

Coefficient HCC 22: 0.363 (Community Non-Dual Aged (CNA))

CMS-HCC V24

Historical

Not used for standard CY2026 Medicare Advantage payment. Select a historical period to review V24.

Not used for CY2026 payment

ACA/HHS

Mapped

HCC 011

HHS-HCC 011 adult, RAF varies...

Code-level coefficient reference

ESRD/PACE

Mapped

HCC 10

Lymphoma and Other Cancers

Code-level coefficient reference

RXHCC

Mapped

HCC 22

Prostate, Breast, Bladder, an...

Code-level coefficient reference

Code Book Path

Official

C56Malignant neoplasm of ovary C56.2Malignant neoplasm of left ovary

Inclusion Terms

Official

No inclusion terms are included in this display for C56.2. Check the code and parent instructions in the Code Book.

Excludes 2

Official

No Excludes 2 notes are included in this display for C56.2. Check the code and parent instructions in the Code Book.

Related Codes

Official

C56.1Malignant neoplasm of right ovary C56.3Malignant neoplasm of bilateral ovaries C56.9Malignant neoplasm of unspecified ovary

Includes

Official

malignant neoplasm of skin of female genital organsInherited from C51-C58

Excludes 1

Official

No Excludes 1 notes are included in this display for C56.2. Check the code and parent instructions in the Code Book.

Code First

Official

No Code First sequencing instructions are included in this display for C56.2. Check the code and parent instructions in the Code Book.

Use Additional

Official

code to identify any functional activityInherited from C56

Code Also

Official

No Code Also instructions are included in this display for C56.2. Check the code and parent instructions in the Code Book.

Buddy Documentation Tip

HCC Buddy guidance

Laterality confirmed as left ovary

Histological type and grade

FIGO staging

Peritoneal cytology and peritoneal spread assessment

MEAT Support

HCC Buddy guidance

Laterality confirmed as left ovary

Histological type and grade

FIGO staging

Peritoneal cytology and peritoneal spread assessment

Audit Caution

HCC Buddy guidance

Laterality errors between C56.1 (right) and C56.2 (left) — always verify against source documentation

Coding Krukenberg tumors or other metastatic ovarian disease as primary ovarian cancer

Using this code for borderline ovarian tumors which have a separate code (D39.12)

Not capturing contralateral ovarian involvement when bilateral disease is present

Common Mistakes

HCC Buddy guidance

C56.1 — Right ovary; laterality reversal error

C56.3 — Bilateral ovaries; use when both sides are confirmed malignant

C56.9 — Unspecified ovary; use only when laterality cannot be determined

C79.62 — Secondary malignant neoplasm of ovary; metastatic disease to the ovary from another primary

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 C56.2 an HCC code?

Yes. C56.2 (Malignant neoplasm of left ovary) maps to HCC 22, Bladder, Colorectal, and Other Cancers under the CMS-HCC V28 risk adjustment model, with a source-labeled community non-dual aged reference coefficient of 0.363. Source-labeled code-level coefficients are references, not member totals. Actual contribution depends on complete member context, hierarchy and cleanup rules, interactions, and model year. HCC Buddy's RAF Calculator supports CMS-HCC V28 PY2026 and shows no score unless every required source and calculation check passes. It is billable for payment year 2026.

Coder answer: C56.2 is billable and maps to V28 HCC 22, Bladder, Colorectal, and Other Cancers. Open it in the Code Book for the tabular path, RAF, and MEAT checklist.

Code: C56.2
Description: Malignant neoplasm of left ovary
HCC (V28): HCC 22 — Bladder, Colorectal, and Other Cancers
RAF reference coefficient: 0.363
Billable: Yes
Payment year: 2026

HCC Category Mapping

V28HCC 22, Bladder, Colorectal, and Other Cancers

0.363

ESRDHCC 10, Lymphoma and Other Cancers

Not separately weighted

RxHCCHCC 22, Prostate, Breast, Bladder, and Other Cancers and Tumors

Not separately weighted

These are source-labeled model coefficients, not member totals. A category may still be removed by hierarchy or model cleanup rules. 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 context, hierarchy and cleanup rules, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains available for historical review.

Work C56.2 in the Code Book — tabular path, V28 RAF reference, and MEAT checklist →

MEAT review for C56.2

For C56.2, confirm that the documentation supports the diagnosis and meets the applicable coding, encounter, program and payer requirements. MEAT (Monitor, Evaluate, Assess, or Treat) is a review mnemonic, not a universal CMS coding rule.

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

Coder workflow notes

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What This Code Means

C56.2 is the ICD-10-CM diagnosis code for malignant neoplasm of left ovary. This code represents cancer that has started in the left ovary, one of the two female reproductive organs that produce eggs. It is used when a malignant (cancerous) tumor is confirmed to be located specifically on the left side. C56.2 sits in the ICD-10-CM chapter for neoplasms (c00-d49), within the section covering malignant neoplasms of female genital organs (c51-c58).

Under the CMS-HCC V28 risk adjustment model, C56.2 maps to Bladder, Colorectal, and Other Cancers (HCC 22) with a source-labeled community, non-dual, aged reference coefficient of 0.363. For CY2026 non-PACE Medicare Advantage, CMS uses 100% of the 2024 CMS-HCC model (V28). PACE uses a separate model blend. Source-labeled code-level coefficients are references, not member totals. Actual contribution depends on complete member context, hierarchy and cleanup rules, interactions, and model year. HCC Buddy's RAF Calculator supports CMS-HCC V28 PY2026 and shows no score unless every required source and calculation check passes.

Ensure laterality is documented in the medical record before assigning this code; if the ovary is not specified as left, right, or bilateral, query the physician for clarification. For C56.2, confirm that the documentation supports the diagnosis and meets the applicable coding, encounter, program and payer requirements. MEAT (Monitor, Evaluate, Assess, or Treat) is a review mnemonic, not a universal CMS coding rule. 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, source-labeled coefficient references, and MEAT documentation criteria for C56.2 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•Ensure laterality is documented in the medical record before assigning this code; if the ovary is not specified as left, right, or bilateral, query the physician for clarification
•This code should be used in conjunction with histology codes (C80.1 series) to specify the type of ovarian cancer (such as serous, mucinous, or clear cell carcinoma) when available

Clinical Significance

Malignant neoplasm of the left ovary carries the same clinical gravity as right-sided disease. Ovarian cancer treatment typically includes surgical staging with total abdominal hysterectomy, bilateral salpingo-oophorectomy, omentectomy, and peritoneal biopsies, followed by platinum-based chemotherapy. Laterality documentation is essential for surgical planning and cancer registry accuracy.

Documentation Requirements

✓Laterality confirmed as left ovary
✓Histological type and grade
✓FIGO staging
✓Peritoneal cytology and peritoneal spread assessment
✓Lymph node status (pelvic and para-aortic)
✓Tumor marker levels (CA-125)
✓BRCA/genetic testing results
✓Residual disease status after surgery

Commonly Confused Codes

•C56.1: Right ovary; laterality reversal error
•C56.3: Bilateral ovaries; use when both sides are confirmed malignant
•C56.9: Unspecified ovary; use only when laterality cannot be determined
•C79.62: Secondary malignant neoplasm of ovary; metastatic disease to the ovary from another primary
•D27.1: Benign neoplasm of left ovary; verify malignancy before assigning cancer code