C91.4 — Hairy cell leukemia

Not billable

Is C91.4 billable?

No — C91.4 is a non-billable header code. C91.4 groups more specific codes and cannot be submitted on a claim. A valid ICD-10-CM code must be reported at the highest level of specificity available in its branch. Select one of the 3 billable codes beneath C91.4.

Billable codes under this header

C91.4 at a glance

Code	C91.4
Description	Hairy cell leukemia
Billable	No — header code
Code set	ICD-10-CM FY2027
Valid for encounters	October 1, 2026 – September 30, 2027

How is C91.4 listed in the Alphabetic Index?

These are the routes through the Alphabetic Index that lead to C91.4. They show the wording a clinician may have documented, which often differs from the Tabular description.

Leukemia, leukemic › hairy cell
Reticuloendotheliosis › leukemic

Inclusion terms

Alternative wording in documentation that is classified to C91.4.

Leukemic reticuloendotheliosis

Excludes1 — never code together — inherited from C91

The conditions below can never be reported together with C91.4 on the same claim. An Excludes1 note means the two conditions cannot occur in the same patient, so reporting both is a coding error.

personal history of leukemia (Z85.6)

Excludes2 — not included here — inherited from C81-C96

The conditions below are not part of C91.4, but a patient may have both at the same time. When documentation supports it, C91.4 and the excluded code may both be reported.

Kaposi's sarcoma of lymph nodes (C46.3)
secondary and unspecified neoplasm of lymph nodes (C77.-)
secondary neoplasm of bone marrow (C79.52)
secondary neoplasm of spleen (C78.89)

What codes fall under C91.4? (3)

How long has C91.4 existed?

C91.4 has been in ICD-10-CM since at least FY2016, the earliest fiscal year on record here.

Derived from the official order files for FY2016–FY2026. FY2017 and FY2020 publish no order file, so those years are not covered.

Which conditions are coded to C91.4?

ICD-10 code for Leukemia