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ICD-10-CM 2027 diagnosis code

B25.0Cytomegaloviral pneumonitis

✓ Billable / specificMCC — major complication/comorbidity

B25.0 is a valid, billable ICD-10-CM code for cytomegaloviral pneumonitis. 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 B25.0

B25.0 is the ICD-10-CM diagnosis code for cytomegaloviral pneumonitis. It belongs to category B25 (cytomegaloviral disease), block B25-B34 (other viral diseases) 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 B25 (cytomegaloviral disease), B25.0 is specifically for cytomegaloviral pneumonitis. Related codes cover cytomegaloviral hepatitis (B25.1), cytomegaloviral pancreatitis (B25.2), other cytomegaloviral diseases (B25.8) and unspecified (B25.9).

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 177 (Respiratory Infections and Inflammations with MCC, relative weight 1.6092), DRG 178 (Respiratory Infections and Inflammations with CC, relative weight 0.9744) and DRG 179 (Respiratory Infections and Inflammations without CC/MCC, relative weight 0.7345), in MDC 04 (Diseases and Disorders of the Respiratory System), 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 078.5 (cytomegaloviral disease) and 484.1 (pneumonia in cytomegalic inclusion disease).

Notes that apply from higher levels

Instructions written at a parent level also apply to B25.0.

› From B25 Cytomegaloviral disease
Excludes1
  • congenital cytomegalovirus infection (P35.1)
  • cytomegaloviral mononucleosis (B27.1-)

Broader instructions also apply from Chapter 1: Certain infectious and parasitic diseases.

Alphabetic index entries

4 entries

Terms in the official ICD-10-CM index that lead to B25.0.

Codes whose notes reference B25.0

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 →
  • 078.5Cytomegaloviral diseaseapproximate, combination
  • 484.1Pneumonia in cytomegalic inclusion diseaseapproximate, combination

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 B25.0

Is B25.0 billable?

Yes. B25.0 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).

Can B25.0 be used as a principal diagnosis?

Yes. The Medicare Code Editor doesn't restrict B25.0 as a principal diagnosis.

Is B25.0 a CC or MCC?

B25.0 is an MCC (major complication or comorbidity) under MS-DRG v44.0, unless excluded by the principal diagnosis.

What DRG does B25.0 group to?

B25.0 is used in the MS-DRG v44.0 logic for MS-DRG 177 (Respiratory Infections and Inflammations with MCC), MS-DRG 178 (Respiratory Infections and Inflammations with CC) and MS-DRG 179 (Respiratory Infections and Inflammations 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 B25.0?

The CMS General Equivalence Mappings map B25.0 to ICD-9-CM 078.5 and 484.1.