H21.339 — Parasitic cyst of iris, ciliary body or anterior chamber, unspecified eye
Is H21.339 billable?
Yes, but H21.339 will trip a Medicare edit. H21.339 is a valid, billable ICD-10-CM code for encounters from October 1, 2026 through September 30, 2027. However, CMS lists H21.339 under Medicare Code Editor edit 20, “Unspecified code” — meaning a code specifying laterality (right, left or bilateral) exists in the same family. On an inpatient claim this triggers the edit, because CMS holds that there are very limited circumstances in which laterality cannot be documented.
H21.339 at a glance
| Code | H21.339 |
|---|---|
| Description | Parasitic cyst of iris, ciliary body or anterior chamber, unspecified eye |
| Billable | Yes |
| Code set | ICD-10-CM FY2027 |
| Valid for encounters | October 1, 2026 – September 30, 2027 |
What Medicare edits apply to H21.339?
The Medicare Code Editor screens inpatient claims before they are grouped. These edits name H21.339 directly.
A code specifying laterality (right, left or bilateral) exists in the same family. CMS holds that there are very limited circumstances in which laterality cannot be documented.
Which MS-DRGs does H21.339 group to?
H21.339 sits in MDC 02 and helps define the logic of 2 MS-DRGs (version 44, FY2027). Which one a stay actually groups to also depends on procedures and secondary diagnoses.
- 121Acute Major Eye Infections with CC/MCCmedical
- 122Acute Major Eye Infections without CC/MCCmedical
As a secondary diagnosis, H21.339 is a complication or comorbidity (CC), which can move a stay into a higher-paying DRG.
How is H21.339 listed in the Alphabetic Index?
The Alphabetic Index lists these routes under H21.33, the nearest indexed parent of H21.339. Use them to find the family, then select the specific code.
- Cyst › iris › parasitic (colloid) (mucous) (simple) (retention)
Excludes2 — not included here — inherited from Chapter 7
The conditions below are not part of H21.339, but a patient may have both at the same time. When documentation supports it, H21.339 and the excluded code may both be reported.
- certain conditions originating in the perinatal period (P04-P96)
- certain infectious and parasitic diseases (A00-B99)
- complications of pregnancy, childbirth and the puerperium (O00-O9A)
- congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)
- diabetes mellitus related eye conditions (E09.3-, E10.3-, E11.3-, E13.3-)
- endocrine, nutritional and metabolic diseases (E00-E88)
- injury (trauma) of eye and orbit (S05.-)
- injury, poisoning and certain other consequences of external causes (S00-T88)
- neoplasms (C00-D49)
- symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)
- syphilis related eye disorders (A50.01, A50.3-, A51.43, A52.71)
Excludes2 — not included here — inherited from H21
The conditions below are not part of H21.339, but a patient may have both at the same time. When documentation supports it, H21.339 and the excluded code may both be reported.
- sympathetic uveitis (H44.1-)
Excludes2 — not included here — inherited from H21.3
The conditions below are not part of H21.339, but a patient may have both at the same time. When documentation supports it, H21.339 and the excluded code may both be reported.
- miotic pupillary cyst (H21.27-)
How long has H21.339 existed?
H21.339 has been in ICD-10-CM since at least FY2016, the earliest fiscal year on record here.
Derived from the official order files for FY2016–FY2026. FY2017 and FY2020 publish no order file, so those years are not covered.