2026 ICD-10-CM Diagnosis Code O99.820Streptococcus B carrier state complicating pregnancy

ICD-10-CM Codes›O00-O9A›O94-O9A›O99

ICD-10-CM O99.820
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

O99.820 is a billable ICD-10-CM diagnosis code for Streptococcus B carrier state complicating pregnancy. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 817 through 819, 831 through 833. The code is restricted by the Medicare Code Editor to maternity cases (age 9 through 64) and not accepted as a principal diagnosis. Coders also document this condition as group B Streptococcus carrier. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Carrier status and Other specified complications in pregnancy.

Code Identity

ICD-10-CM Code
O99.820
Billable Status
Yes — Valid for Submission
Code Describes
Streptococcus B carrier state complicating pregnancy
Short Description
Streptococcus B carrier state complicating pregnancy
Same as the full description in the CMS dataset.
Parent Code
O99.82
Streptococcus B carrier state complicating pregnancy, childbirth and the puerperium

Code Classification

ChapterO00-O9APregnancy, childbirth and the puerperium
SectionO94-O9AOther obstetric conditions, not elsewhere classified
CategoryO99Other maternal diseases classifiable elsewhere but complicating pregnancy, childbirth and the puerperium
This CodeO99.820Streptococcus B carrier state complicating pregnancy

Code EditsBilling

Medicare Code Editor checks that affect claim validity for O99.820.

Maternity diagnoses
The Medicare Code Editor detects inconsistencies in maternity cases by checking a patient's age and any diagnosis on the patient's record. The maternity code edits apply to patients age ange is 9–64 years inclusive (e.g., diabetes in pregnancy, antepartum pulmonary complication).
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.

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Group B Streptococcus carrier
  • Group B streptococcus carrier complicating pregnancy
  • Streptococcus carrier

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

    • Pregnancy(single) (uterine)
      • complicated by (care of) (management affected by)
        • infection (s)
          • carrier state NEC
            • streptococcus B
    • Pregnancy(single) (uterine)
      • complicated by (care of) (management affected by)
        • streptococcus group B (GBS) carrier state

Clinical ClassificationClinical

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

CCSR FAC024
Carrier status
Default principal diagnosis: inpatient No · outpatient No
CCSR PRG028
Other specified complications in pregnancy
Default principal diagnosis: inpatient No · outpatient Yes

Patient EducationClinical

Infections and Pregnancy

During pregnancy, some common infections such as the common cold or a skin infection do not usually cause serious problems. Some infections, such as the flu, can be more severe when you're pregnant. But other infections can be harmful to you, your fetus, or both.

The full article covers:

  • How can infections affect your pregnancy?
  • What infections can be harmful during pregnancy?
  • What are the symptoms of an infection during pregnancy?
  • What are the treatments for infections during pregnancy?
  • Can infections during pregnancy be prevented?

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert O99.820 to ICD-9-CMHistory

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

ICD-9-CM
648.93 Oth curr cond-antepartum
ApproximateCombination The match is approximate, and more than one code can be needed to describe the source diagnosis. Confirm with contextual judgment.
ICD-9-CM
V02.51 Group b streptoc carrier
ApproximateCombination The match is approximate, and more than one code can be needed to describe the source diagnosis. Confirm with contextual judgment.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About O99.820Overview

Is O99.820 a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report Streptococcus B carrier state complicating pregnancy on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does O99.820 group to?

On inpatient claims, Streptococcus B carrier state complicating pregnancy maps to MS-DRG 817, 818, 819, 831, 832, 833, with relative weights from 0.5229 to 1.6880 depending on complications. Higher weights mean higher Medicare reimbursement.

Can O99.820 be a principal diagnosis?

No. The Medicare Code Editor rejects this code as a principal diagnosis because Streptococcus B carrier state complicating pregnancy describes a circumstance that influences health status rather than a current illness. Report it as a secondary diagnosis.

Who can O99.820 be reported for?

The Medicare Code Editor checks Streptococcus B carrier state complicating pregnancy against patient demographics: this code is intended for maternity cases (age 9 through 64). Claims outside these limits are flagged as inconsistent.

What is the ICD-9 equivalent of O99.820?

Under the General Equivalence Mappings, Streptococcus B carrier state complicating pregnancy converts to ICD-9-CM 648.93 (oth curr cond-antepartum) and V02.51 (group b streptoc carrier). The mapping is approximate, so confirm the match fits the documentation.

Footnotes

[1] Not chronic - A diagnosis code that does not fit the criteria for chronic condition (duration, ongoing medical treatment, and limitations) is considered not chronic. Some codes designated as not chronic are acute conditions. Other diagnosis codes that indicate a possible chronic condition, but for which the duration of the illness is not specified in the code description (i.e., we do not know the condition has lasted 12 months or longer) also are considered not chronic.