ICD-10 Code C91.90 – Lymphoid leukemia, unspecified not having achieved remission (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code C91.90 – Lymphoid leukemia, unspecified not having achieved remission
What it is
C91.90 identifies lymphoid leukemia when the subtype is not specified and the disease has not gone into remission. Use it for a documented lymphoid leukemia diagnosis without a more precise classification.
Clinical signs
Clinical features vary; refer to documentation. Common findings in leukemia may include fatigue, infections, bruising, anemia, or enlarged lymph nodes, but you should code only what is documented.
When to use this code
Use this code when the provider documents lymphoid leukemia and states it is not in remission, but does not identify a more specific subtype. It is also appropriate when the record confirms active disease and the exact lymphoid lineage is unspecified. If remission status is unclear, check documentation before assigning the code.
Do not use for
Do not use C91.90 if the leukemia subtype is documented more specifically, such as a distinct lymphocytic or lymphoblastic diagnosis. Also avoid it when the record says the condition is in remission or when documentation is insufficient.
Coding tip
Code the highest level of specificity available, and verify whether the provider documents remission status separately.