MS-DRG 98 – Non-Bacterial Infection of Nervous System Except Viral Meningitis with CC
A Medical DRG in MDC 01 (Diseases & Disorders of the Nervous System). Inpatient cases group to DRG 98 when the ICD-10-CM principal diagnosis is one of the 81 codes listed below and a secondary diagnosis on the complication or comorbidity (CC) list is present. Its FY 2026 relative weight is 2.2949 with a geometric mean length of stay of 5.9 days.
Severity family
The grouper first assigns the case to MDC 01 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 MCC → 97; with CC → 98; without CC/MCC → 99.
Principal Diagnosis Codes 81 codes · 30 categories
A06 Amebiasis1 code
- A06.6 Amebic brain abscess
A27 Leptospirosis2 codes
A50 Congenital syphilis6 codes
A51 Early syphilis1 code
- A51.41 Secondary syphilitic meningitis
A52 Late syphilis3 codes
A80 Acute poliomyelitis6 codes
- A80.0 Acute paralytic poliomyelitis, vaccine-associated
- A80.1 Acute paralytic poliomyelitis, wild virus, imported
- A80.2 Acute paralytic poliomyelitis, wild virus, indigenous
- A80.30 Acute paralytic poliomyelitis, unspecified
- A80.39 Other acute paralytic poliomyelitis
- A80.9 Acute poliomyelitis, unspecified
A83 Mosquito-borne viral encephalitis9 codes
- A83.0 Japanese encephalitis
- A83.1 Western equine encephalitis
- A83.2 Eastern equine encephalitis
- A83.3 St Louis encephalitis
- A83.4 Australian encephalitis
- A83.5 California encephalitis
- A83.6 Rocio virus disease
- A83.8 Other mosquito-borne viral encephalitis
- A83.9 Mosquito-borne viral encephalitis, unspecified
A84 Tick-borne viral encephalitis5 codes
A85 Other viral encephalitis, not elsewhere classified4 codes
A86 Unspecified viral encephalitis1 code
- A86 Unspecified viral encephalitis
A88 Other viral infections of central nervous system, not elsewhere classified1 code
- A88.8 Other specified viral infections of central nervous system
A89 Unspecified viral infection of central nervous system1 code
- A89 Unspecified viral infection of central nervous system
A92 Other mosquito-borne viral fevers1 code
- A92.2 Venezuelan equine fever
B00 Herpesviral [herpes simplex] infections2 codes
B01 Varicella [chickenpox]2 codes
B02 Zoster [herpes zoster]1 code
- B02.24 Postherpetic myelitis
B05 Measles1 code
- B05.0 Measles complicated by encephalitis
B06 Rubella [German measles]3 codes
B10 Other human herpesviruses2 codes
B26 Mumps1 code
- B26.2 Mumps encephalitis
B37 Candidiasis1 code
- B37.5 Candidal meningitis
B38 Coccidioidomycosis1 code
- B38.4 Coccidioidomycosis meningitis
B45 Cryptococcosis1 code
- B45.1 Cerebral cryptococcosis
B58 Toxoplasmosis1 code
- B58.2 Toxoplasma meningoencephalitis
G02 Meningitis in other infectious and parasitic diseases classified elsewhere1 code
- G02 Meningitis in other infectious and parasitic diseases classified elsewhere
G03 Meningitis due to other and unspecified causes4 codes
G04 Encephalitis, myelitis and encephalomyelitis12 codes
- G04.00 Acute disseminated encephalitis and encephalomyelitis, unspecified
- G04.01 Postinfectious acute disseminated encephalitis and encephalomyelitis (postinfectious ADEM)
- G04.02 Postimmunization acute disseminated encephalitis, myelitis and encephalomyelitis
- G04.30 Acute necrotizing hemorrhagic encephalopathy, unspecified
- G04.31 Postinfectious acute necrotizing hemorrhagic encephalopathy
- G04.32 Postimmunization acute necrotizing hemorrhagic encephalopathy
- G04.39 Other acute necrotizing hemorrhagic encephalopathy
- G04.81 Other encephalitis and encephalomyelitis
- G04.82 Acute flaccid myelitis
- G04.89 Other myelitis
- G04.90 Encephalitis and encephalomyelitis, unspecified
- G04.91 Myelitis, unspecified
G05 Encephalitis, myelitis and encephalomyelitis in diseases classified elsewhere2 codes
Procedure Codes
Frequently Asked Questions
What is MS-DRG 98?
MS-DRG 98 (Non-Bacterial Infection of Nervous System Except Viral Meningitis with CC) is a medical DRG in MDC 01 (Diseases & Disorders of the Nervous System). Its FY 2026 relative weight is 2.2949 with a geometric mean length of stay of 5.9 days.
What is the difference between DRG 97, 98, 99?
All 3 share the same base category; the severity of secondary diagnoses separates them: 97 (with MCC), 98 (with CC), 99 (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 98?
81 ICD-10-CM principal diagnosis codes group to this DRG, spanning 30 three-character categories.
What is the relative weight of DRG 98?
The FY 2026 relative weight of this DRG is 2.2949, meaning reimbursement of roughly 2.29 times the average Medicare inpatient case. Multiply by a hospital's blended base rate for the approximate payment.
