A21.1 ICD-10-CM Code: Oculoglandular tularemia
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FY 2026 Apr update / Certain infectious and parasitic diseases (A00-B99) / Certain zoonotic bacterial diseases (A20-A28)
A21.1
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidanceOculoglandular tularemia
Oculoglandular tularemia is a bacterial infection caused by Francisella tularensis that affects the eye and nearby lymph nodes, typically occurring after the bacteria enters through the conjunctiva (eye membrane). This form of tularemia causes eye irritation, discharge, and swollen lymph nodes in front of the ear.
CMS-HCC V28
N/A—
Not mapped
CMS-HCC V24
N/A—
Not mapped
ACA/HHS
N/A—
Not mapped
ESRD/PACE
N/A—
Not mapped
RXHCC
N/A—
Not mapped
Code Book Path
Inclusion Terms
Official- Ophthalmic tularemia
Excludes 2
OfficialICD-10-CM does not list Excludes 2 notes for A21.1 in this effective period.
Related Child Codes
Includes
Official- deer-fly fever
- infection due to Francisella tularensis
- rabbit fever
Excludes 1
OfficialICD-10-CM does not list Excludes 1 notes for A21.1 in this effective period.
Code First
OfficialICD-10-CM does not list Code First sequencing instructions for A21.1 in this effective period.
Use Additional
OfficialICD-10-CM does not list Use Additional Code instructions for A21.1 in this effective period.
Code Also
OfficialICD-10-CM does not list Code Also instructions for A21.1 in this effective period.
Buddy Documentation Tip
Current with CMS: FY2026 ICD-10-CM Apr 1 update (effective Apr 1 – Sep 30, 2026) · CMS-HCC V28, 100% phased in for payment year 2026. FY2027 code set already staged for October 1, 2026. How HCC Buddy stays current →
Is A21.1 an HCC code?
No. A21.1 is a billable ICD-10-CM code but does not map to any HCC category in V28, V24, ESRD, or RxHCC.
- Code
- A21.1
- Description
- Oculoglandular tularemia
- HCC (V28)
- No CMS-HCC V28 mapping
- RAF
- —
- Billable
- Yes
- Payment year
- 2026
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
A21.1 is the ICD-10-CM diagnosis code for oculoglandular tularemia. Oculoglandular tularemia is a bacterial infection caused by Francisella tularensis that affects the eye and nearby lymph nodes, typically occurring after the bacteria enters through the conjunctiva (eye membrane). This form of tularemia causes eye irritation, discharge, and swollen lymph nodes in front of the ear. A21.1 sits in the ICD-10-CM chapter for certain infectious and parasitic diseases (a00-b99), within the section covering certain zoonotic bacterial diseases (a20-a28).
A21.1 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.
Verify that the infection specifically involves ocular (eye) manifestations with regional lymphadenopathy to distinguish from other forms of tularemia (A21.0, A21.2, A21.3, A21.8, A21.9).
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for A21.1 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Verify that the infection specifically involves ocular (eye) manifestations with regional lymphadenopathy to distinguish from other forms of tularemia (A21.0, A21.2, A21.3, A21.8, A21.9)
- •Document the source of exposure if known (animal contact, tick bite, contaminated water) as this may support medical necessity and help with epidemiological tracking