Non-Billable / Non-Specific Code
ICD-10-CM C91.5 is the diagnosis code for Adult T-cell lymphoma/leukemia (HTLV-1-associated). This code falls under the section "Malignant neoplasms of lymphoid, hematopoietic and related tissue" within Chapter 2 — Neoplasms (C00-D49). It is a non-billable/non-specific ICD-10-CM code that should not be used for reimbursement. A more specific sub-code is required for billing. Medical coders and healthcare providers use this code to document and classify diagnoses in electronic health records, insurance claims, and clinical databases.
Understanding where C91.5 sits in the ICD-10-CM classification helps ensure proper coding:
No, C91.5 is a non-billable/non-specific code. You should use a more specific sub-code for billing and reimbursement.
C91.5 is the ICD-10-CM diagnosis code for "Adult T-cell lymphoma/leukemia (HTLV-1-associated)". It is used by healthcare providers to classify and document this condition in medical records and insurance claims.
The parent code of C91.5 is C91 ("Lymphoid leukemia"). C91.5 provides a more specific classification within this category.
C91.5 is located in Section C81-C96 — "Malignant neoplasms of lymphoid, hematopoietic and related tissue" within Chapter 2 of the ICD-10-CM Tabular List.
C91.5 has 3 sub-code(s) that provide more specific detail: C91.50, C91.51, C91.52.
Use C91.5 when the patients documented diagnosis matches "Adult T-cell lymphoma/leukemia (HTLV-1-associated)" and the clinical documentation supports this level of specificity. Always verify with the latest ICD-10-CM guidelines and payer requirements.
The ICD-10-CM code for Adult T-cell lymphoma/leukemia (HTLV-1-associated) is C91.5.
No, C91.5 is non-billable. Use a more specific sub-code for primary diagnosis billing.
C91.5 is in Chapter 2 of the ICD-10-CM Tabular List.
Yes, C91.5 is a valid ICD-10-CM code for the 2026 fiscal year, subject to official CMS updates.