ICD-10-CM 2027
ICD-10 code for Monocytosis
From the official ICD-10-CM alphabetic index entry “Monocytosis (symptomatic)”. Page updated September 29, 2026.
About coding Monocytosis
The ICD-10-CM code for Monocytosis is D72.821 (Monocytosis (symptomatic)).
Within D72.82 (elevated white blood cell count), D72.821 is specifically for Monocytosis (symptomatic). Related codes cover Lymphocytosis (symptomatic) (D72.820), Plasmacytosis (D72.822), Leukemoid reaction (D72.823), Basophilia (D72.824), Bandemia (D72.825), other elevated white blood cell count (D72.828) and unspecified (D72.829).
Don't report D72.821 together with the conditions in its Excludes1 note: infectious mononucleosis (B27.-).
It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.
Don't confuse with (Excludes1 for D72.821)
- infectious mononucleosis (B27.-)
Common questions about Monocytosis ICD-10 codes
What is the ICD-10 code for Monocytosis?
- D72.821 — Monocytosis (symptomatic).
Is D72.821 billable?
- Yes. D72.821 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can D72.821 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict D72.821 as a principal diagnosis.
Is D72.821 a CC or MCC?
- No. D72.821 is neither a CC nor an MCC under MS-DRG v44.0.