2027 ICD-10-CM Diagnosis Code O99.820Streptococcus B carrier state complicating pregnancy
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 2027 (October 1, 2026 through September 30, 2027) 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 colonization by Streptococcus agalactiae during pregnancy. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Carrier status and Other specified complications in pregnancy.
Code Identity
Code Classification
Code EditsBilling
Medicare Code Editor checks that affect claim validity for O99.820.
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Colonization by Streptococcus agalactiae during pregnancy
- Group B Streptococcus carrier
- Group B streptococcus carrier complicating pregnancy
- Streptococcus carrier
Instructional NotesGuidance
Instructions from the official ICD-10-CM Tabular List that apply to O99.820: its own notes plus those printed at O99.82, O99.8, O99, and Chapter 15. 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.
- conditions which complicate the pregnant state, are aggravated by the pregnancy or are a main reason for obstetric care
Excludes1
Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.
- Carrier of streptococcus group B (GBS) in a nonpregnant woman (Z22.330)
- supervision of normal pregnancy (Z34.-)
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.
- genitourinary infections in pregnancy (O23.-)
- infection of genitourinary tract following delivery (O86.1-O86.4)
- malignant neoplasm complicating pregnancy, childbirth and the puerperium (O9A.1-)
- maternal care for known or suspected abnormality of maternal pelvic organs (O34.-)
- postpartum acute kidney failure (O90.49)
- traumatic injuries in pregnancy (O9A.2-)
Use Additional Code
Add a second code, after this one, to fully describe the condition.
- code to identify condition
- code to identify specific condition
- code, if applicable, from category Z3A, Weeks of gestation, to identify the specific week of the pregnancy, if known.
Notes
General instructions on how these codes are used.
- CODES FROM THIS CHAPTER ARE FOR USE ONLY ON MATERNAL RECORDS, NEVER ON NEWBORN RECORDS
- Codes from this chapter are for use for conditions related to or aggravated by the pregnancy, childbirth, or by the puerperium (maternal causes or obstetric causes)
- Trimesters are counted from the first day of the last menstrual period. They are defined as follows:
- 1st trimester- less than 14 weeks 0 days
- 2nd trimester- 14 weeks 0 days to less than 28 weeks 0 days
- 3rd trimester- 28 weeks 0 days until delivery
Source: CMS ICD-10-CM Tabular List. How to read instructional notes.
Referenced in Other NotesGuidance
Instructional notes printed at other codes that name O99.820, its category, or a range that includes it.
Excludes1 1
These codes carry an Excludes1 note naming O99.820: they are not reported together with it, unless the two conditions are unrelated.
Excludes2 1
These codes carry an Excludes2 note naming O99.820: its condition is not part of those codes, and both may be reported when the patient has both.
Index to Diseases and InjuriesGuidance
Alphabetical index entries that point to this code.
Pregnancy (single) (uterine) See Also: Delivery and Puerperal; Z33.1
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
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.
Code HistoryHistory
Questions About O99.820Overview
What is the ICD-10 code for Streptococcus B carrier state complicating pregnancy?
The ICD-10-CM code for Streptococcus B carrier state complicating pregnancy is O99.820 (sometimes written as O99820). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
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, 2026 through September 30, 2027.
What MS-DRG does O99.820 group to?
On inpatient claims, Streptococcus B carrier state complicating pregnancy maps to MS-DRG 833, 832, 831, 819, 818, 817, with relative weights from 0.5000 to 1.7586 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.
