ICD-10-CM 2027 diagnosis code
P23.9Congenital pneumonia, unspecified
P23.9 is a valid, billable ICD-10-CM code for congenital pneumonia, unspecified. 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 P23.9
P23.9 is the ICD-10-CM diagnosis code for congenital pneumonia, unspecified. It belongs to category P23 (congenital pneumonia), block P19-P29 (respiratory and cardiovascular disorders specific to the perinatal period) and chapter 16 (certain conditions originating in the perinatal period). It is billable, so it can be reported on its own for dates of service from October 1, 2026 through September 30, 2027.
Within P23, choose P23.9 (unspecified) only when documentation doesn't support a more specific option: due to viral agent (P23.0), due to Chlamydia (P23.1), due to staphylococcus (P23.2), due to streptococcus, group B (P23.3), due to Escherichia coli (P23.4), due to Pseudomonas (P23.5), due to other bacterial agents (P23.6) and due to other organisms (P23.8).
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 791 (Prematurity with Major Problems, relative weight 4.1075) and DRG 793 (Full Term Neonate with Major Problems, relative weight 4.2195), in MDC 15 (Newborns and Other Neonates with Conditions Originating in the Perinatal Period), 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 770.0 (congenital pneumonia).
Notes that apply from higher levels
Instructions written at a parent level also apply to P23.9.
› From P23 Congenital pneumonia
- infective pneumonia acquired in utero or during birth
- neonatal pneumonia resulting from aspiration (P24.-)
Broader instructions also apply from Chapter 16: Certain conditions originating in the perinatal period.
Alphabetic index entries
2 entriesTerms in the official ICD-10-CM index that lead to P23.9.
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 15 · Newborns and Other Neonates with Conditions Originating in the Perinatal Period
MDC 15 · Newborns and Other Neonates with Conditions Originating in the Perinatal Period
ICD-9-CM equivalent
Converter →- 770.0Congenital pneumoniaapproximate
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 P23.9
Is P23.9 billable?
- Yes. P23.9 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can P23.9 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict P23.9 as a principal diagnosis.
Is P23.9 a CC or MCC?
- P23.9 is an MCC (major complication or comorbidity) under MS-DRG v44.0, unless excluded by the principal diagnosis.
What DRG does P23.9 group to?
- P23.9 is used in the MS-DRG v44.0 logic for MS-DRG 791 (Prematurity with Major Problems) and MS-DRG 793 (Full Term Neonate with Major Problems). 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 P23.9?
- The CMS General Equivalence Mappings map P23.9 to ICD-9-CM 770.0.