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C90.02 ICD-10-CM Code: Multiple myeloma in relapse

C90.02 maps to CMS-HCC V28 19. A source-labeled RAF reference is available. Documentation must support MEAT. MEAT criteria · RAF Calculator · HCC coding software

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FY 2026 Apr update / Neoplasms (C00-D49) / Malignant neoplasms of lymphoid, hematopoietic and related tissue (C81-C96)

C90.02

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

Multiple myeloma in relapse

Multiple myeloma that has returned or worsened after a period of remission or improvement.

Buddy the Bee presenting code insight

Buddy Insight

Multiple myeloma in relapse indicates the disease has returned after a period of remission, with rising monoclonal protein levels, reappearance of bone marrow plasmacytosis, or recurrence of end-organ damage.

CMS-HCC V28

HCC 19

Code-level coefficient reference

CMS-HCC V24

Historical

Historical

Not used for CY2026 payment

ACA/HHS

HCC 009

Code-level coefficient reference

ESRD/PACE

HCC 9

Code-level coefficient reference

RXHCC

HCC 16

Code-level coefficient reference

Code Book Path

Official
C90Multiple myeloma and malignant plasma cell neoplasms
C90.0Multiple myeloma
C90.02Multiple myeloma in relapse

Inclusion Terms

Official
  • Kahler's disease
  • Medullary plasmacytoma
  • Myelomatosis
  • Plasma cell myeloma

Excludes 2

Official

ICD-10-CM does not list Excludes 2 notes for C90.02 in this effective period.

Related Child Codes

Official
C90.00Multiple myeloma not having achieved remission
C90.01Multiple myeloma in remission

Includes

Official

ICD-10-CM does not list Includes notes for C90.02 in this effective period.

Excludes 1

Official
  • solitary myeloma (C90.3-)
  • solitary plasmactyoma (C90.3-)

Code First

Official

ICD-10-CM does not list Code First sequencing instructions for C90.02 in this effective period.

Use Additional

Official

ICD-10-CM does not list Use Additional Code instructions for C90.02 in this effective period.

Code Also

Official

ICD-10-CM does not list Code Also instructions for C90.02 in this effective period.

Buddy Documentation Tip

HCC Buddy guidance
Documentation must include evidence of biochemical or clinical relapse based on IMWG criteria, such as rising monoclonal protein, new bone lesions, worsening anemia, or hypercalcemia.
The timeline from prior remission to relapse, prior treatment regimens, new treatment plan, and current disease burden must be documented.

MEAT Support

HCC Buddy guidance
Documentation must include evidence of biochemical or clinical relapse based on IMWG criteria, such as rising monoclonal protein, new bone lesions, worsening anemia, or hypercalcemia.
The timeline from prior remission to relapse, prior treatment regimens, new treatment plan, and current disease burden must be documented.

Audit Caution

HCC Buddy guidance
Relapse requires documented prior remission followed by disease recurrence
do not use this code for primary refractory disease that never achieved remission. Distinguish between biochemical relapse (rising lab values) and clinical relapse (symptom recurrence) in documentation. Ensure prior treatment history supports the relapse designation.

Common Mistakes

HCC Buddy guidance
C90.00 (multiple myeloma not in remission) is for initial non-response to treatment, not relapse.
C90.01 (multiple myeloma in remission) indicates response without recurrence.
D47.2 (monoclonal gammopathy of undetermined significance) is a premalignant condition unrelated to relapse.

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 C90.02 an HCC code?

Yes. C90.02 (Multiple myeloma in relapse) maps to HCC 19, Myelodysplastic Syndromes, Multiple Myeloma, and Other Cancers under the CMS-HCC V28 risk adjustment model, with a source-labeled community non-dual aged reference coefficient of 1.798. 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: C90.02 is billable and maps to V28 HCC 19, Myelodysplastic Syndromes, Multiple Myeloma, and Other Cancers. Open it in the Code Book for the tabular path, RAF, and MEAT checklist.

Code
C90.02
Description
Multiple myeloma in relapse
HCC (V28)
HCC 19 — Myelodysplastic Syndromes, Multiple Myeloma, and Other Cancers
RAF reference coefficient
1.798
Billable
Yes
Payment year
2026

HCC Category Mapping

V28HCC 19, Myelodysplastic Syndromes, Multiple Myeloma, and Other Cancers
1.798
ESRDHCC 9, Lung and Other Severe Cancers
Not separately weighted
RxHCCHCC 16, Multiple Myeloma and Other Hematologic Cancers
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 C90.02 in the Code Book — tabular path, V28 RAF reference, and MEAT checklist →

MEAT Criteria for C90.02

For C90.02 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 C90.02 during that encounter, not just copy-forwarded from a problem list.

Coder workflow notes

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What This Code Means

C90.02 is the ICD-10-CM diagnosis code for multiple myeloma in relapse. Multiple myeloma that has returned or worsened after a period of remission or improvement. C90.02 sits in the ICD-10-CM chapter for neoplasms (c00-d49), within the section covering malignant neoplasms of lymphoid, hematopoietic and related tissue (c81-c96).

Under the CMS-HCC V28 risk adjustment model, C90.02 maps to Myelodysplastic Syndromes, Multiple Myeloma, and Other Cancers (HCC 19) with a source-labeled community, non-dual, aged reference coefficient of 1.798. No V24 mapping is shown for C90.02; use the applicable model and payment year when reviewing the V28 mapping. 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. 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.

Relapse (fifth character '2') indicates the cancer has returned after remission; distinguish from initial diagnosis. Because C90.02 maps to an HCC category, the provider's documentation must satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) before the diagnosis is used for risk adjustment. 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 C90.02 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

  • •Relapse (fifth character '2') indicates the cancer has returned after remission; distinguish from initial diagnosis
  • •Document the timeline of remission and relapse to support medical necessity for treatment decisions

Clinical Significance

Multiple myeloma in relapse indicates the disease has returned after a period of remission, with rising monoclonal protein levels, reappearance of bone marrow plasmacytosis, or recurrence of end-organ damage. Relapsed myeloma typically requires a change in treatment regimen, as the disease may have developed resistance to prior therapy. Each successive relapse generally portends a shorter subsequent remission duration.

Documentation Requirements

  • ✓Documentation must include evidence of biochemical or clinical relapse based on IMWG criteria, such as rising monoclonal protein, new bone lesions, worsening anemia, or hypercalcemia.
  • ✓The timeline from prior remission to relapse, prior treatment regimens, new treatment plan, and current disease burden must be documented.

Commonly Confused Codes

  • •C90.00 (multiple myeloma not in remission) is for initial non-response to treatment, not relapse.
  • •C90.01 (multiple myeloma in remission) indicates response without recurrence.
  • •D47.2 (monoclonal gammopathy of undetermined significance) is a premalignant condition unrelated to relapse.

Child Codes

C90.00Multiple myeloma not having achieved remission
HCC 19
C90.01Multiple myeloma in remission
HCC 19
C90.02Multiple myeloma in relapse
HCC 19

Code Hierarchy

└C90Multiple myeloma and malignant plasma cell neoplasms└C90.0Multiple myeloma└C90.02Multiple myeloma in relapse
└C90.02Multiple myeloma in relapse

Because C90.02 maps to an HCC category, the documentation must satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) before the diagnosis is used for risk adjustment.

C90.02 maps to CMS-HCC V28 category 19, Myelodysplastic Syndromes, Multiple Myeloma, and Other Cancers. See the ICD-10 to HCC mapping hub for how the V28 crosswalk works. The mapping identifies a payment HCC category for C90.02. Review its source-labeled HCC coefficient above, check the RAF Calculator with complete member context for CMS-HCC V28 PY2026, and confirm the documentation the chart needs before the code is submitted. HCC Buddy shows no RAF score unless every required source and calculation check passes.

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