MCMCB Pro
H33.121

H33.121Parasitic cyst of retina, right eye

Billable / specific codeICD-10-CMright

H33.121 is a billable, specific ICD-10-CM code for parasitic cyst of retina, right eye. It is valid for submission on a claim.

Risk adjustment

H33.121 does not map to an HCC and does not risk-adjust under CMS-HCC V28. That is normal — most ICD-10 codes do not. It still needs to be coded correctly; it just will not move a RAF score.

Medicare coverage

H33.121 is named in 8 Medicare coverage policies 8 listing it as supporting medical necessity. Which of them applies to you depends on your Medicare contractor, and coverage genuinely differs by state.

  • A53008Billing and Coding: Intraocular Bevacizumab
  • A53060Billing and Coding: Ophthalmology: Extended Ophthalmoscopy and Fundus Photography
  • A56726Billing and Coding: Ophthalmology: Posterior Segment Imaging (Extended Ophthalmoscopy and Fundus Photography)
  • A56729Billing and Coding: Magnetic Resonance Imaging of the Head and Neck

Related codes at this level

Codes that share H33.12. If H33.121 is not quite right, the correct code is usually one of these.

Questions about H33.121

Is H33.121 a billable ICD-10-CM code?
Yes. H33.121 is a billable, specific ICD-10-CM code and is valid for submission on a claim.
Where does H33.121 sit in the tabular list?
Diseases of the eye and adnexa (H00-H59), in the block Disorders of choroid and retina (H30-H36).
ICD-10-CMFY2026-Apr· effective April 1, 2026

Loaded directly from the CMS/NCHS ICD-10-CM public-domain release — see data sources and our editorial policy. If this page disagrees with the CMS tabular list, this page is wrong. Reference information for professional coders; not medical or billing advice.