MS-DRG 121 – Acute Major Eye Infections with CC/MCC
A Medical DRG in MDC 02 (Diseases & Disorders of the Eye). Inpatient cases group to DRG 121 when the ICD-10-CM principal diagnosis is one of the 77 codes listed below and a secondary diagnosis on the CC or MCC lists is present. Its FY 2026 relative weight is 1.1633 with a geometric mean length of stay of 4.1 days.
Severity family
The grouper first assigns the case to MDC 02 from the principal diagnosis and finds no qualifying operating-room procedure (this is a Medical DRG; ICD-10-PCS codes do not drive assignment here), then applies the severity split from secondary diagnoses: with CC/MCC → 121; without CC/MCC → 122.
Principal Diagnosis Codes 77 codes · 6 categories
H04 Disorders of lacrimal system12 codes
- H04.011 Acute dacryoadenitis, right lacrimal gland
- H04.012 Acute dacryoadenitis, left lacrimal gland
- H04.013 Acute dacryoadenitis, bilateral lacrimal glands
- H04.019 Acute dacryoadenitis, unspecified lacrimal gland
- H04.321 Acute dacryocystitis of right lacrimal passage
- H04.322 Acute dacryocystitis of left lacrimal passage
- H04.323 Acute dacryocystitis of bilateral lacrimal passages
- H04.329 Acute dacryocystitis of unspecified lacrimal passage
- H04.331 Acute lacrimal canaliculitis of right lacrimal passage
- H04.332 Acute lacrimal canaliculitis of left lacrimal passage
- H04.333 Acute lacrimal canaliculitis of bilateral lacrimal passages
- H04.339 Acute lacrimal canaliculitis of unspecified lacrimal passage
H05 Disorders of orbit16 codes
- H05.011 Cellulitis of right orbit
- H05.012 Cellulitis of left orbit
- H05.013 Cellulitis of bilateral orbits
- H05.019 Cellulitis of unspecified orbit
- H05.021 Osteomyelitis of right orbit
- H05.022 Osteomyelitis of left orbit
- H05.023 Osteomyelitis of bilateral orbits
- H05.029 Osteomyelitis of unspecified orbit
- H05.031 Periostitis of right orbit
- H05.032 Periostitis of left orbit
- H05.033 Periostitis of bilateral orbits
- H05.039 Periostitis of unspecified orbit
- H05.041 Tenonitis of right orbit
- H05.042 Tenonitis of left orbit
- H05.043 Tenonitis of bilateral orbits
- H05.049 Tenonitis of unspecified orbit
H16 Keratitis24 codes
- H16.001 Unspecified corneal ulcer, right eye
- H16.002 Unspecified corneal ulcer, left eye
- H16.003 Unspecified corneal ulcer, bilateral
- H16.009 Unspecified corneal ulcer, unspecified eye
- H16.011 Central corneal ulcer, right eye
- H16.012 Central corneal ulcer, left eye
- H16.013 Central corneal ulcer, bilateral
- H16.019 Central corneal ulcer, unspecified eye
- H16.031 Corneal ulcer with hypopyon, right eye
- H16.032 Corneal ulcer with hypopyon, left eye
- H16.033 Corneal ulcer with hypopyon, bilateral
- H16.039 Corneal ulcer with hypopyon, unspecified eye
- H16.061 Mycotic corneal ulcer, right eye
- H16.062 Mycotic corneal ulcer, left eye
- H16.063 Mycotic corneal ulcer, bilateral
- H16.069 Mycotic corneal ulcer, unspecified eye
- H16.071 Perforated corneal ulcer, right eye
- H16.072 Perforated corneal ulcer, left eye
- H16.073 Perforated corneal ulcer, bilateral
- H16.079 Perforated corneal ulcer, unspecified eye
- H16.311 Corneal abscess, right eye
- H16.312 Corneal abscess, left eye
- H16.313 Corneal abscess, bilateral
- H16.319 Corneal abscess, unspecified eye
H21 Other disorders of iris and ciliary body4 codes
- H21.331 Parasitic cyst of iris, ciliary body or anterior chamber, right eye
- H21.332 Parasitic cyst of iris, ciliary body or anterior chamber, left eye
- H21.333 Parasitic cyst of iris, ciliary body or anterior chamber, bilateral
- H21.339 Parasitic cyst of iris, ciliary body or anterior chamber, unspecified eye
H33 Retinal detachments and breaks4 codes
H44 Disorders of globe17 codes
- H44.001 Unspecified purulent endophthalmitis, right eye
- H44.002 Unspecified purulent endophthalmitis, left eye
- H44.003 Unspecified purulent endophthalmitis, bilateral
- H44.009 Unspecified purulent endophthalmitis, unspecified eye
- H44.011 Panophthalmitis (acute), right eye
- H44.012 Panophthalmitis (acute), left eye
- H44.013 Panophthalmitis (acute), bilateral
- H44.019 Panophthalmitis (acute), unspecified eye
- H44.021 Vitreous abscess (chronic), right eye
- H44.022 Vitreous abscess (chronic), left eye
- H44.023 Vitreous abscess (chronic), bilateral
- H44.029 Vitreous abscess (chronic), unspecified eye
- H44.121 Parasitic endophthalmitis, unspecified, right eye
- H44.122 Parasitic endophthalmitis, unspecified, left eye
- H44.123 Parasitic endophthalmitis, unspecified, bilateral
- H44.129 Parasitic endophthalmitis, unspecified, unspecified eye
- H44.19 Other endophthalmitis
Procedure Codes
Frequently Asked Questions
What is MS-DRG 121?
MS-DRG 121 (Acute Major Eye Infections with CC/MCC) is a medical DRG in MDC 02 (Diseases & Disorders of the Eye). Its FY 2026 relative weight is 1.1633 with a geometric mean length of stay of 4.1 days.
What is the difference between DRG 121, 122?
All 2 share the same base category; the severity of secondary diagnoses separates them: 121 (with CC/MCC), 122 (without CC/MCC). A major complication or comorbidity (MCC) places the case in the highest-weighted DRG of the family; a CC in the middle; neither in the lowest.
How many diagnosis codes group to DRG 121?
77 ICD-10-CM principal diagnosis codes group to this DRG, spanning 6 three-character categories.
What is the relative weight of DRG 121?
The FY 2026 relative weight of this DRG is 1.1633, meaning reimbursement of roughly 1.16 times the average Medicare inpatient case. Multiply by a hospital's blended base rate for the approximate payment.
