2027 ICD-10-CM Diagnosis Code B97.21SARS-associated coronavirus as the cause of diseases classified elsewhere

ICD-10-CM Codes›A00–B99›B95-B97›B97

ICD-10-CM B97.21
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

B97.21 is a billable ICD-10-CM diagnosis code for SARS-associated coronavirus as the cause of diseases classified elsewhere. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 865 through 866. As a secondary diagnosis, it counts as a complication or comorbidity (CC) and moves an inpatient stay to a higher severity level within its MS-DRG family. It does not count, however, when the principal diagnosis is one of 133 closely related codes. The code is not accepted as a principal diagnosis by the Medicare Code Editor. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Viral infection.

Code Identity

ICD-10-CM Code
B97.21
Billable Status
Yes — Valid for Submission
Code Describes
SARS-associated coronavirus as the cause of diseases classified elsewhere
Short Description
SARS-associated coronavirus causing diseases classd elswhr
Parent Code
B97.2
Coronavirus as the cause of diseases classified elsewhere

Code Classification

ChapterA00–B99Certain infectious and parasitic diseases
SectionB95-B97Bacterial and viral infectious agents
CategoryB97Viral agents as the cause of diseases classified elsewhere
This CodeB97.21SARS-associated coronavirus as the cause of diseases classified elsewhere

Code EditsBilling

Medicare Code Editor checks that affect claim validity for B97.21.

Unacceptable principal diagnosis
There are selected codes that describe a circumstance which influences an individual's health status but not a current illness or injury, or codes that are not specific manifestations but may be due to an underlying cause. These codes are considered unacceptable as a principal diagnosis.

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to B97.21: its own notes plus those printed at block B95-B97 and Chapter 1. A note printed at a category, block or chapter applies to every code under it.

Includes

Further defines, or gives examples of, the content of the category.

From Chapter 1 (A00-B99) Certain infectious and parasitic diseases applies to 1,068 codes
  • diseases generally recognized as communicable or transmissible

Excludes1

Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.

  • pneumonia due to SARS-associated coronavirus (J12.81)

Excludes2

Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.

From Chapter 1 (A00-B99) Certain infectious and parasitic diseases applies to 1,068 codes
  • carrier or suspected carrier of infectious disease (Z22.-)
  • certain localized infections - see body system-related chapters
  • infectious and parasitic diseases complicating pregnancy, childbirth and the puerperium (O98.-)
  • infectious and parasitic diseases specific to the perinatal period (P35-P39)
  • influenza and other acute respiratory infections (J00-J22)

Use Additional Code

Add a second code, after this one, to fully describe the condition.

From Chapter 1 (A00-B99) Certain infectious and parasitic diseases applies to 1,068 codes
  • code to identify resistance to antimicrobial drugs (Z16.-)

Notes

General instructions on how these codes are used.

From Block B95-B97 Bacterial and viral infectious agents applies to 46 codes
  • These categories are provided for use as supplementary or additional codes to identify the infectious agent(s) in diseases classified elsewhere.

Source: CMS ICD-10-CM Tabular List. How to read instructional notes.

Referenced in Other NotesGuidance

Instructional notes printed at other codes that name B97.21, its category, or a range that includes it.

Excludes1 1

These codes carry an Excludes1 note naming B97.21: they are not reported together with it, unless the two conditions are unrelated.

  • B34 Viral infection of unspecified site
    viral agents as the cause of diseases classified elsewhere (B97.-) names B97.-, which includes this code

Excludes2 1

These codes carry an Excludes2 note naming B97.21: its condition is not part of those codes, and both may be reported when the patient has both.

  • U07.1 COVID-19
    coronavirus as the cause of diseases classified elsewhere (B97.2-) names B97.2-, which includes this code

Use Additional Code 52

These codes say to use an additional code from the note, and B97.21 is one of the codes named.

  • J95.851 Ventilator associated pneumonia
    code to identify the organism, if known (B95.-, B96.-, B97.-) names B97.-, which includes this code
  • P23.0 Congenital pneumonia due to viral agent
    code (B97) to identify organism names B97, which includes this code
  • E06.0 Acute thyroiditis
    code (B95-B97) to identify infectious agent. names B95-B97, which includes this code
  • G06 Intracranial and intraspinal abscess and granuloma
    code (B95-B97) to identify infectious agent. names B95-B97, which includes this code
  • H65 Nonsuppurative otitis media
    infectious agent (B95-B97) names B95-B97, which includes this code
  • I30.1 Infective pericarditis
    code (B95-B97) to identify infectious agent names B95-B97, which includes this code
  • I33.0 Acute and subacute infective endocarditis
    code (B95-B97) to identify infectious agent names B95-B97, which includes this code
  • I40.0 Infective myocarditis
    code (B95-B97) to identify infectious agent names B95-B97, which includes this code
  • J01 Acute sinusitis
    code (B95-B97) to identify infectious agent. names B95-B97, which includes this code
  • J02.8 Acute pharyngitis due to other specified organisms
    code (B95-B97) to identify infectious agent names B95-B97, which includes this code
  • J03.8 Acute tonsillitis due to other specified organisms
    code (B95-B97) to identify infectious agent. names B95-B97, which includes this code
  • J04 Acute laryngitis and tracheitis
    code (B95-B97) to identify infectious agent. names B95-B97, which includes this code
  • J05 Acute obstructive laryngitis [croup] and epiglottitis
    code (B95-B97) to identify infectious agent. names B95-B97, which includes this code
  • J06.9 Acute upper respiratory infection, unspecified
    code (B95-B97) to identify infectious agent, if known, such as: names B95-B97, which includes this code
  • J32 Chronic sinusitis
    infectious agent (B95-B97) names B95-B97, which includes this code

37 more Use Additional Code notes name this code. Browse all Use Additional Code notes.

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR INF008
Viral infection
Default principal diagnosis: inpatient No · outpatient No

Convert B97.21 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
079.82 SARS assoc coronavirus
Exact Match The mapping is direct, with no qualifiers.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About B97.21Overview

Is B97.21 (Coronavirus as the cause of diseases classified elsewhere) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report SARS-associated coronavirus as the cause of diseases classified elsewhere on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

What MS-DRG does B97.21 group to?

On inpatient claims, SARS-associated coronavirus as the cause of diseases classified elsewhere maps to MS-DRG 866, 865, with relative weights from 0.8691 to 1.3153 depending on complications. Higher weights mean higher Medicare reimbursement.

Is B97.21 a CC or MCC?

CMS lists B97.21 as a CC (complication or comorbidity) for FY 2027. Reported as a secondary diagnosis, it moves the inpatient stay to a higher-weighted DRG within its severity family. It does not count when the principal diagnosis is one of the 133 closely related codes in its exclusion list.

Can B97.21 be a principal diagnosis?

No. The Medicare Code Editor rejects this code as a principal diagnosis because SARS-associated coronavirus as the cause of diseases classified elsewhere describes a circumstance that influences health status rather than a current illness. Report it as a secondary diagnosis.

Can B97.21 be reported with J12.81?

Not as a rule. The Excludes1 note on B97.21 lists "pneumonia due to SARS-associated coronavirus (J12.81)". An Excludes1 note means the excluded code is never reported together with this one; the only exception is when the two conditions are unrelated to each other (Official Guidelines, Section I.A.12.a).