Is C91.4 a billable ICD-10-CM code?

No. C91.4 is a non-billable header code. Code to a higher level of specificity using one of its child codes.

Where does C91.4 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 C91.4?

C91.4 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 C91.4 (C91) and apply to it just the same.

C91.4

C91.4 — Hairy cell leukemia

Non-billable headerICD-10-CM

C91.4 is a non-billable header ICD-10-CM code for hairy cell leukemia. It cannot be billed on its own: choose one of the more specific child codes below.

Inclusion terms

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

Leukemic reticuloendotheliosis

Excludes1 inherited from the categories above C91.4

These are not written on C91.4, but they bind it: a note on a category applies to every code beneath it. Billing C91.4 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 C91.4

These codes carry an Excludes1 note pointing at C91.4. The conflict binds both ways, but ICD-10-CM only writes it down on one side — so you would not find this by reading C91.4 alone.

C94Other leukemias of specified cell type
D61.81Pancytopenia
D72.825Bandemia
D76Other specified diseases with participation of lymphoreticular and reticulohistiocytic tissue

Risk adjustment

C91.4 does not map to an HCC and does not risk-adjust under CMS-HCC V28. That is normal — most ICD-10 codes do not. It still needs to be coded correctly; it just will not move a RAF score.

Code history

C91.4 has not changed since FY2024 — no addition, revision or deletion across the three most recent ICD-10-CM releases.

Code to one of these instead C91.4

3 child codes. Green means billable.

Related codes at this level

Codes that share C91. If C91.4 is not quite right, the correct code is usually one of these.

Questions about C91.4

Is C91.4 a billable ICD-10-CM code?: No. C91.4 is a non-billable header code. Code to a higher level of specificity using one of its child codes.
Where does C91.4 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 C91.4?: C91.4 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 C91.4 (C91) and apply to it just the same.