D72.821 ICD-10-CM Code: Monocytosis (symptomatic)
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FY 2026 Apr update / Diseases of the blood and blood-forming organs and certain disorders involving the immune mechanism (D50-D89) / Other disorders of blood and blood-forming organs (D70-D77)
D72.821
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidanceMonocytosis (symptomatic)
An abnormally high number of monocytes (a type of white blood cell) in the blood that is causing symptoms. Monocytes help fight infections and clear dead cells, and elevated levels may indicate infection or inflammation.
CMS-HCC V28
00
RAF 0
CMS-HCC V24
00
RAF 0
ACA/HHS
00
RAF 0
ESRD/PACE
00
RAF 0
RXHCC
00
RAF 0
Code Trumping
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Code Book Path
Inclusion Terms
OfficialICD-10-CM does not list inclusion terms for D72.821 in this effective period.
Excludes 2
OfficialICD-10-CM does not list Excludes 2 notes for D72.821 in this effective period.
Related Child Codes
Includes
OfficialICD-10-CM does not list Includes notes for D72.821 in this effective period.
Excludes 1
Official- infectious mononucleosis (B27.-)
Code First
OfficialICD-10-CM does not list Code First sequencing instructions for D72.821 in this effective period.
Use Additional
OfficialICD-10-CM does not list Use Additional Code instructions for D72.821 in this effective period.
Code Also
OfficialICD-10-CM does not list Code Also instructions for D72.821 in this effective period.
Buddy Documentation Tip
Last updated: FY2026 ICD-10-CM Apr update, Apr 1, 2026 through Sep 30, 2026. CMS-HCC V28 is 100% phased in for payment year 2026.
Is D72.821 an HCC code?
No. D72.821 is a billable ICD-10-CM code but does not map to any HCC category in V28, V24, ESRD, or RxHCC.
Coder workflow notes
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This code does not map to an HCC category in any model (V28, V24, ESRD, RxHCC).
What This Code Means
D72.821 is the ICD-10-CM diagnosis code for monocytosis (symptomatic). An abnormally high number of monocytes (a type of white blood cell) in the blood that is causing symptoms. Monocytes help fight infections and clear dead cells, and elevated levels may indicate infection or inflammation. D72.821 sits in the ICD-10-CM chapter for diseases of the blood and blood-forming organs and certain disorders involving the immune mechanism (d50-d89), within the section covering other disorders of blood and blood-forming organs (d70-d77).
D72.821 is a billable ICD-10-CM code but does not map to a payment HCC under the CMS-HCC V28, V24, ESRD, or RxHCC risk adjustment models. It can be reported on Medicare Advantage encounter data submissions but it does not contribute to a beneficiary's RAF score and therefore does not affect risk-adjusted payments to the plan.
Ensure documentation specifically mentions monocytosis with symptoms to justify this code.
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for D72.821 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Ensure documentation specifically mentions monocytosis with symptoms to justify this code
- •Investigate whether this is a reactive process (infection, inflammation) or part of a hematologic disorder
Excludes 1, Do NOT code together
- infectious mononucleosis (B27.-)