C56.3 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 coding software

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Code lookupC56.3

Effective periodFY2026 Apr Update (Apr 1-Sep 30)

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

C56.3

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

Malignant neoplasm of bilateral ovaries

Cancer that affects both ovaries simultaneously or involves both ovaries as part of the same malignant process.

Buddy Insight

Bilateral ovarian cancer indicates malignancy affecting both ovaries, which may represent synchronous primary cancers or advanced disease with contralateral spread.

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 C56.3Malignant neoplasm of bilateral ovaries

Inclusion Terms

Official

No inclusion terms are included in this display for C56.3. Check the code and parent instructions in the Code Book.

Excludes 2

Official

No Excludes 2 notes are included in this display for C56.3. Check the code and parent instructions in the Code Book.

Related Codes

Official

C56.1Malignant neoplasm of right ovary C56.2Malignant neoplasm of left ovary 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 C56.3. Check the code and parent instructions in the Code Book.

Code First

Official

No Code First sequencing instructions are included in this display for C56.3. 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 C56.3. Check the code and parent instructions in the Code Book.

Buddy Documentation Tip

HCC Buddy guidance

Bilateral ovarian involvement confirmed by imaging, surgery, or pathology

Determination of whether bilateral involvement is primary or metastatic

Histological type and grade for each ovary if pathology is different

FIGO staging reflecting bilateral disease

MEAT Support

HCC Buddy guidance

Bilateral ovarian involvement confirmed by imaging, surgery, or pathology

Determination of whether bilateral involvement is primary or metastatic

Histological type and grade for each ovary if pathology is different

FIGO staging reflecting bilateral disease

Audit Caution

HCC Buddy guidance

Coding bilateral disease as two separate unilateral codes instead of using the bilateral code C56.3

Not distinguishing between synchronous bilateral primaries and metastatic spread from one ovary to the other

Using unspecified laterality when both ovaries are involved — bilateral is a specific designation

Failing to capture genetic susceptibility codes (Z15.01) when hereditary cancer syndrome is identified in the context of bilateral disease

Common Mistakes

HCC Buddy guidance

C56.1 + C56.2 — Some coders may assign separate codes for each ovary instead of the bilateral code; C56.3 is the correct single code for bilateral disease

C56.9 — Unspecified ovary; use only when laterality is truly unknown, not for bilateral disease

C79.62 — Secondary malignant neoplasm of ovary; use when bilateral involvement is metastatic from another primary site

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 C56.3 an HCC code?

Yes. C56.3 (Malignant neoplasm of bilateral ovaries) 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: C56.3 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: C56.3
Description: Malignant neoplasm of bilateral ovaries
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 C56.3 in the Code Book — tabular path, V28 RAF reference, and MEAT checklist →

MEAT review for C56.3

For C56.3, 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

C56.3 is the ICD-10-CM diagnosis code for malignant neoplasm of bilateral ovaries. Cancer that affects both ovaries simultaneously or involves both ovaries as part of the same malignant process. C56.3 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, C56.3 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.

Distinguish between primary bilateral ovarian cancer and metastatic disease from one ovary to the other. For C56.3, 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 C56.3 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•Distinguish between primary bilateral ovarian cancer and metastatic disease from one ovary to the other
•Document whether cancers are synchronous (occurring at same time) or metachronous (occurring at different times)

Clinical Significance

Bilateral ovarian cancer indicates malignancy affecting both ovaries, which may represent synchronous primary cancers or advanced disease with contralateral spread. Bilateral involvement is common in high-grade serous ovarian cancer and typically indicates at least stage IB disease. This distinction is important for staging, prognosis, and genetic counseling as bilateral disease increases suspicion for hereditary cancer syndromes.

Documentation Requirements

✓Bilateral ovarian involvement confirmed by imaging, surgery, or pathology
✓Determination of whether bilateral involvement is primary or metastatic
✓Histological type and grade for each ovary if pathology is different
✓FIGO staging reflecting bilateral disease
✓Peritoneal involvement assessment
✓Lymph node status
✓BRCA and hereditary cancer testing (bilateral disease increases suspicion)
✓CA-125 levels and tumor marker trends

Commonly Confused Codes

•C56.1 + C56.2: Some coders may assign separate codes for each ovary instead of the bilateral code; C56.3 is the correct single code for bilateral disease
•C56.9: Unspecified ovary; use only when laterality is truly unknown, not for bilateral disease
•C79.62: Secondary malignant neoplasm of ovary; use when bilateral involvement is metastatic from another primary site