Is C91.1 a billable ICD-10-CM code?

No. C91.1 is a non-billable header code. Code to a higher level of specificity using one of its child codes.

Where does C91.1 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 C91.1?

C91.1 carries an Excludes1 note, which means the conditions it lists can never be coded together with it on the same encounter.

C91.1

C91.1 — Chronic lymphocytic leukemia of B-cell type

Non-billable headerICD-10-CM

C91.1 is a non-billable header ICD-10-CM code for chronic lymphocytic leukemia of b-cell type. It cannot be billed on its own: choose one of the more specific child codes below.

Excludes1 — never code together

These conditions cannot occur together. Billing both on the same encounter is a denial.

lymphoplasmacytic lymphoma (C83.0-)

Inclusion terms

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

Lymphoplasmacytic leukemia
Richter syndrome

Other codes that can never be billed with C91.1

These codes carry an Excludes1 note pointing at C91.1. The conflict binds both ways, but ICD-10-CM only writes it down on one side — so you would not find this by reading C91.1 alone.

C83.0Small cell B-cell lymphoma
C84.ZOther mature T/NK-cell lymphomas

Risk adjustment

C91.1 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 to one of these instead C91.1

3 child codes. Green means billable.

Related codes at this level

Codes that share C91. If C91.1 is not quite right, the correct code is usually one of these.

Questions about C91.1

Is C91.1 a billable ICD-10-CM code?: No. C91.1 is a non-billable header code. Code to a higher level of specificity using one of its child codes.
Where does C91.1 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 C91.1?: C91.1 carries an Excludes1 note, which means the conditions it lists can never be coded together with it on the same encounter.