H21.312 ICD-10-CM Code: Exudative cysts of iris or anterior chamber, left eye
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FY 2026 Apr update / Diseases of the eye and adnexa (H00-H59) / Disorders of sclera, cornea, iris and ciliary body (H15-H22)
H21.312
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidanceExudative cysts of iris or anterior chamber, left eye
Fluid-filled sacs in the iris or front part of the eye caused by fluid leakage, occurring in the left eye.
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
OfficialICD-10-CM does not list inclusion terms for H21.312 in this effective period.
Excludes 2
OfficialICD-10-CM does not list Excludes 2 notes for H21.312 in this effective period.
Related Child Codes
Includes
OfficialICD-10-CM does not list Includes notes for H21.312 in this effective period.
Excludes 1
OfficialICD-10-CM does not list Excludes 1 notes for H21.312 in this effective period.
Code First
OfficialICD-10-CM does not list Code First sequencing instructions for H21.312 in this effective period.
Use Additional
OfficialICD-10-CM does not list Use Additional Code instructions for H21.312 in this effective period.
Code Also
OfficialICD-10-CM does not list Code Also instructions for H21.312 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 H21.312 an HCC code?
No. H21.312 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
H21.312 is the ICD-10-CM diagnosis code for exudative cysts of iris or anterior chamber, left eye. Fluid-filled sacs in the iris or front part of the eye caused by fluid leakage, occurring in the left eye. H21.312 sits in the ICD-10-CM chapter for diseases of the eye and adnexa (h00-h59), within the section covering disorders of sclera, cornea, iris and ciliary body (h15-h22).
H21.312 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.
Exudative cysts result from fluid accumulation; ensure documentation specifies this type rather than idiopathic or implantation cysts.
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for H21.312 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Exudative cysts result from fluid accumulation; ensure documentation specifies this type rather than idiopathic or implantation cysts.
- •Confirm left eye laterality is documented; if bilateral, use H21.313 instead.