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ICD-10-CM 2027 diagnosis code

H33.123Parasitic cyst of retina, bilateral

✓ Billable / specificCC — complication/comorbidity

H33.123 is a valid, billable ICD-10-CM code for parasitic cyst of retina, bilateral. It can be reported on claims for dates of service from October 1, 2026 – September 30, 2027.

Code unchanged since ICD-10-CM took effect on October 1, 2015. Source: official FY2027 ICD-10-CM release from CDC/NCHS and CMS. Page updated September 29, 2026. About our data

About H33.123

H33.123 is the ICD-10-CM diagnosis code for parasitic cyst of retina, bilateral. It belongs to category H33 (retinal detachments and breaks), block H30-H36 (disorders of choroid and retina) and chapter 7 (diseases of the eye and adnexa). It is billable, so it can be reported on its own for dates of service from October 1, 2026 through September 30, 2027.

Within H33.12 (parasitic cyst of retina), H33.123 is specifically for parasitic cyst of retina, bilateral. Related codes cover right eye (H33.121), left eye (H33.122) and unspecified eye (H33.129).

As a secondary diagnosis it is a CC (complication or comorbidity), which can move an inpatient stay into the "with CC" MS-DRG of its family, unless the principal diagnosis excludes it.

In MS-DRG v44.0, it is part of the grouping logic for DRG 121 (Acute Major Eye Infections with CC/MCC, relative weight 1.2255) and DRG 122 (Acute Major Eye Infections without CC/MCC, relative weight 0.7406), in MDC 02 (Diseases and Disorders of the Eye), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.

It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.

Before ICD-10, this condition was coded in ICD-9-CM as 360.13 (parasitic endophthalmitis NOS).

Notes that apply from higher levels

Instructions written at a parent level also apply to H33.123.

› From H33.1 Retinoschisis and retinal cysts
Excludes1
  • congenital retinoschisis (Q14.1)
  • microcystoid degeneration of retina (H35.42-)
› From H33 Retinal detachments and breaks
Excludes1

Broader instructions also apply from Chapter 7: Diseases of the eye and adnexa.

MS-DRG v44.0 grouping

All DRGs →

Inpatient MS-DRGs this diagnosis can group to, as the principal or a secondary diagnosis, depending on the rest of the claim.

ICD-9-CM equivalent

Converter →
  • 360.13Parasitic endophthalmitis NOSapproximate

From the CMS 2018 General Equivalence Mappings (GEMs), the final GEMs release.

Code history

  1. 2016
  2. 2017
  3. 2018
  4. 2019
  5. 2020
  6. 2021
  7. 2022
  8. 2023
  9. 2024
  10. 2025
  11. 2026
  12. 2027
  • FY2016 (effective 10/1/2015): Added (first year of ICD-10-CM)
  • No changes since FY2016.

Common questions about H33.123

Is H33.123 billable?

Yes. H33.123 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).

Can H33.123 be used as a principal diagnosis?

Yes. The Medicare Code Editor doesn't restrict H33.123 as a principal diagnosis.

Is H33.123 a CC or MCC?

H33.123 is a CC (complication or comorbidity) under MS-DRG v44.0, unless excluded by the principal diagnosis.

What DRG does H33.123 group to?

H33.123 is used in the MS-DRG v44.0 logic for MS-DRG 121 (Acute Major Eye Infections with CC/MCC) and MS-DRG 122 (Acute Major Eye Infections without CC/MCC). Which one applies depends on whether it is the principal diagnosis and on the rest of the claim.

What is the ICD-9 code for H33.123?

The CMS General Equivalence Mappings map H33.123 to ICD-9-CM 360.13.