ICD-10-CM 2027 diagnosis code
B45.1Cerebral cryptococcosis
B45.1 is a valid, billable ICD-10-CM code for cerebral cryptococcosis. 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 B45.1
B45.1 is the ICD-10-CM diagnosis code for cerebral cryptococcosis. It belongs to category B45 (cryptococcosis), block B35-B49 (mycoses) and chapter 1 (certain infectious and parasitic diseases). It is billable, so it can be reported on its own for dates of service from October 1, 2026 through September 30, 2027.
Within B45 (cryptococcosis), B45.1 is specifically for cerebral cryptococcosis. Related codes cover pulmonary cryptococcosis (B45.0), cutaneous cryptococcosis (B45.2), osseous cryptococcosis (B45.3), disseminated cryptococcosis (B45.7), other forms of cryptococcosis (B45.8) and unspecified (B45.9).
As a secondary diagnosis it is an MCC (major complication or comorbidity), which can move an inpatient stay into the highest-paying "with MCC" 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 023 (Craniotomy with Major Device Implant or Acute Complex CNS Principal Diagnosis with MCC or Antineoplastic Implant or Epilepsy with Neurostimulator, relative weight 5.7444), DRG 024 (Craniotomy with Major Device Implant or Acute Complex CNS Principal Diagnosis without MCC, relative weight 3.9708), DRG 097 (Non-Bacterial Infection of Nervous System Except Viral Meningitis with MCC, relative weight 3.8226), DRG 098 (Non-Bacterial Infection of Nervous System Except Viral Meningitis with CC, relative weight 2.2706), DRG 099 (Non-Bacterial Infection of Nervous System Except Viral Meningitis without CC/MCC, relative weight 1.5256), DRG 791 (Prematurity with Major Problems, relative weight 4.1075) and 1 more, in MDC 01 (Diseases and Disorders of the Nervous System) and MDC 15 (Newborns and Other Neonates with Conditions Originating in the Perinatal Period), 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 117.5 (cryptococcosis) and 321.0 (Cryptococcal meningitis).
Coding notes
- Cryptococcal meningitis
- Cryptococcosis meningocerebralis
Notes that apply from higher levels
Instructions written at a parent level also apply to B45.1.
Broader instructions also apply from B35-B49 Mycoses and Chapter 1: Certain infectious and parasitic diseases.
Alphabetic index entries
8 entriesTerms in the official ICD-10-CM index that lead to B45.1.
- Cryptococcosis, cryptococcus (infection) (neoformans) › cerebral
- Cryptococcosis, cryptococcus (infection) (neoformans) › meningitis
- Cryptococcosis, cryptococcus (infection) (neoformans) › meningocerebralis
- Encephalitis (chronic) (hemorrhagic) (idiopathic) (nonepidemic) (spurious) (subacute) › Torula, torular (cryptococcal)
- Meningitis (basal) (basic) (brain) (cerebral) (cervical) (congestive) (diffuse) (hemorrhagic) (infantile) (membranous) (metastatic) (nonspecific) (pontine) (progressive) (simple) (spinal) (subacute) (sympathetic) (toxic) › cryptococcal
- Meningitis (basal) (basic) (brain) (cerebral) (cervical) (congestive) (diffuse) (hemorrhagic) (infantile) (membranous) (metastatic) (nonspecific) (pontine) (progressive) (simple) (spinal) (subacute) (sympathetic) (toxic) › Torula histolytica (cryptococcal)
- Meningoencephalomyelitis › due to › Torula
- Meningomyelitis › cryptococcal
Codes whose notes reference B45.1
- G02Excludes1
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.
MDC 01 · Diseases and Disorders of the Nervous System
MDC 01 · Diseases and Disorders of the Nervous System
MDC 15 · Newborns and Other Neonates with Conditions Originating in the Perinatal Period
MDC 15 · Newborns and Other Neonates with Conditions Originating in the Perinatal Period
ICD-9-CM equivalent
Converter →From the CMS 2018 General Equivalence Mappings (GEMs), the final GEMs release.
Code history
- 2016
- 2017
- 2018
- 2019
- 2020
- 2021
- 2022
- 2023
- 2024
- 2025
- 2026
- 2027
- FY2016 (effective 10/1/2015): Added (first year of ICD-10-CM)
- No changes since FY2016.
Common questions about B45.1
Is B45.1 billable?
- Yes. B45.1 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can B45.1 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict B45.1 as a principal diagnosis.
Is B45.1 a CC or MCC?
- B45.1 is an MCC (major complication or comorbidity) under MS-DRG v44.0, unless excluded by the principal diagnosis.
What DRG does B45.1 group to?
- B45.1 is used in the MS-DRG v44.0 logic for MS-DRG 023 (Craniotomy with Major Device Implant or Acute Complex CNS Principal Diagnosis with MCC or Antineoplastic Implant or Epilepsy with Neurostimulator), MS-DRG 024 (Craniotomy with Major Device Implant or Acute Complex CNS Principal Diagnosis without MCC), MS-DRG 097 (Non-Bacterial Infection of Nervous System Except Viral Meningitis with MCC), MS-DRG 098 (Non-Bacterial Infection of Nervous System Except Viral Meningitis with CC), MS-DRG 099 (Non-Bacterial Infection of Nervous System Except Viral Meningitis without CC/MCC), MS-DRG 791 (Prematurity with Major Problems) and 1 more. 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 B45.1?
- The CMS General Equivalence Mappings map B45.1 to ICD-9-CM 117.5 and 321.0.