ICD-10-CM 2027 diagnosis code
O99.820Streptococcus B carrier state complicating pregnancy
O99.820 is a valid, billable ICD-10-CM code for streptococcus b carrier state complicating pregnancy. 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 O99.820
O99.820 is the ICD-10-CM diagnosis code for streptococcus B carrier state complicating pregnancy. It belongs to category O99 (other maternal diseases classifiable elsewhere but complicating pregnancy, childbirth and the puerperium), block O94-O9A (other obstetric conditions, not elsewhere classified) and chapter 15 (pregnancy, childbirth and the puerperium). It is billable, so it can be reported on its own for dates of service from October 1, 2026 through September 30, 2027.
Within O99.82 (streptococcus B carrier state complicating pregnancy, childbirth and the puerperium), O99.820 is specifically for streptococcus B carrier state complicating pregnancy. Related codes cover childbirth (O99.824) and the puerperium (O99.825).
Use an additional code to identify specific condition.
It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.
In MS-DRG v44.0, it is part of the grouping logic for DRG 817 (Other Antepartum Diagnoses with O.R. Procedures with MCC, relative weight 2.0534), DRG 818 (Other Antepartum Diagnoses with O.R. Procedures with CC, relative weight 1.2942), DRG 819 (Other Antepartum Diagnoses with O.R. Procedures without CC/MCC, relative weight 0.7739), DRG 831 (Other Antepartum Diagnoses without O.R. Procedures with MCC, relative weight 1.1558), DRG 832 (Other Antepartum Diagnoses without O.R. Procedures with CC, relative weight 0.7585) and DRG 833 (Other Antepartum Diagnoses without O.R. Procedures without CC/MCC, relative weight 0.5002), in MDC 14 (Pregnancy, Childbirth and the Puerperium), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.
The Medicare Code Editor treats this as a maternity diagnosis, expected only for patients age 9 through 64.
It is not acceptable as the principal diagnosis for an inpatient stay; it may be reported as a secondary diagnosis.
It is on the CMS list of diagnoses consistent only with female patients (the sex-conflict edit itself was retired in FY2025).
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 648.93 (other current conditions classifiable elsewhere of mother, antepartum condition or complication) and V02.51 (carrier or suspected carrier of group B streptococcus).
Notes that apply from higher levels
Instructions written at a parent level also apply to O99.820.
› From O99.82 Streptococcus B carrier state complicating pregnancy, childbirth and the puerperium
- Carrier of streptococcus group B (GBS) in a nonpregnant woman (Z22.330)
› From O99.8 Other specified diseases and conditions complicating pregnancy, childbirth and the puerperium
- 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-)
- code to identify condition
› From O99 Other maternal diseases classifiable elsewhere but complicating pregnancy, childbirth and the puerperium
- conditions which complicate the pregnant state, are aggravated by the pregnancy or are a main reason for obstetric care
- code to identify specific condition
Broader instructions also apply from Chapter 15: Pregnancy, childbirth and the puerperium.
Alphabetic index entries
2 entriesTerms in the official ICD-10-CM index that lead to O99.820.
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 14 · Pregnancy, Childbirth and the Puerperium
ICD-9-CM equivalent
Converter →- 648.93Other current conditions classifiable elsewhere of mother, antepartum condition or complicationapproximate, combination
- V02.51Carrier or suspected carrier of group B streptococcusapproximate, combination
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 O99.820
Is O99.820 billable?
- Yes. O99.820 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can O99.820 be used as a principal diagnosis?
- No. It is not acceptable as the principal diagnosis for an inpatient stay; it may be reported as a secondary diagnosis.
Is O99.820 a CC or MCC?
- No. O99.820 is neither a CC nor an MCC under MS-DRG v44.0.
What DRG does O99.820 group to?
- O99.820 is used in the MS-DRG v44.0 logic for MS-DRG 817 (Other Antepartum Diagnoses with O.R. Procedures with MCC), MS-DRG 818 (Other Antepartum Diagnoses with O.R. Procedures with CC), MS-DRG 819 (Other Antepartum Diagnoses with O.R. Procedures without CC/MCC), MS-DRG 831 (Other Antepartum Diagnoses without O.R. Procedures with MCC), MS-DRG 832 (Other Antepartum Diagnoses without O.R. Procedures with CC) and MS-DRG 833 (Other Antepartum Diagnoses without O.R. Procedures without CC/MCC). Which one applies depends on whether it is the principal diagnosis and on the rest of the claim.