Is C91.50 a billable ICD-10-CM code?

Yes. C91.50 is a billable, specific ICD-10-CM code and is valid for submission on a claim.

Where does C91.50 sit in the tabular list?

Neoplasms (C00-D49), in the block Malignant neoplasms of lymphoid, hematopoietic and related tissue (C81-C96).

What cannot be coded together with C91.50?

C91.50 carries Excludes1 notes, which means the conditions they list can never be coded together with it on the same encounter. Some are written on the categories above C91.50 (C91) and apply to it just the same.

C91.50

C91.50 — Adult T-cell lymphoma/leukemia (HTLV-1-associated) not having achieved remission

Billable / specific codeICD-10-CM

C91.50 is a billable, specific ICD-10-CM code for adult t-cell lymphoma/leukemia (htlv-1-associated) not having achieved remission. It is valid for submission on a claim.

Inclusion terms

Alternative wordings a physician may use in the chart for this same code.

Adult T-cell lymphoma/leukemia (HTLV-1-associated) with failed remission
Adult T-cell lymphoma/leukemia (HTLV-1-associated) NOS

Excludes1 inherited from the categories above C91.50

These are not written on C91.50, but they bind it: a note on a category applies to every code beneath it. Billing C91.50 with anything listed here is a denial.

Written on C91 — Lymphoid leukemia

personal history of leukemia (Z85.6)

Other codes that can never be billed with C91.50

These codes carry an Excludes1 note pointing at C91.50. The conflict binds both ways, but ICD-10-CM only writes it down on one side — so you would not find this by reading C91.50 alone.

D72.825Bandemia

Risk adjustment

C91.50 risk-adjusts. Under the CMS-HCC V28 model it maps to this category:

HCC 19 Myelodysplastic Syndromes, Multiple Myeloma, and Other Cancers1.798 RAF

Coefficient shown for the Community Non-dual Aged segment. A higher HCC in the same hierarchy will suppress this one, so capturing it does not always add score.

Medicare coverage

C91.50 is named in 43 Medicare coverage policies — 43 listing it as supporting medical necessity. Which of them applies to you depends on your Medicare contractor, and coverage genuinely differs by state.

A52479Oral Anticancer Drugs - Policy Article
A52479Oral Anticancer Drugs - Policy Article
A52479Oral Anticancer Drugs - Policy Article
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Code history

C91.50 has not changed since FY2024 — no addition, revision or deletion across the three most recent ICD-10-CM releases.

Related codes at this level

Codes that share C91.5. If C91.50 is not quite right, the correct code is usually one of these.

Questions about C91.50

Is C91.50 a billable ICD-10-CM code?: Yes. C91.50 is a billable, specific ICD-10-CM code and is valid for submission on a claim.
Where does C91.50 sit in the tabular list?: Neoplasms (C00-D49), in the block Malignant neoplasms of lymphoid, hematopoietic and related tissue (C81-C96).
What cannot be coded together with C91.50?: C91.50 carries Excludes1 notes, which means the conditions they list can never be coded together with it on the same encounter. Some are written on the categories above C91.50 (C91) and apply to it just the same.