2027 ICD-10-CM Diagnosis Code P23.1Congenital pneumonia due to Chlamydia
ICD-10-CM Codes›P00–P96›P19-P29›P23
- Billable — Valid for Submission
- MCC — Major Complication or Comorbidity
- Not Chronic
P23.1 is a billable ICD-10-CM diagnosis code for congenital pneumonia due to Chlamydia. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 791, 793. As a secondary diagnosis, it counts as a major complication or comorbidity (MCC) and places an inpatient stay in the highest severity level of its MS-DRG family. It does not count, however, when the principal diagnosis is one of 68 closely related codes. Coders also document this condition as Chlamydia pneumoniae infection. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Bacterial infections, Perinatal infections, and Respiratory perinatal condition.
Code Identity
Code Classification
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Chlamydia pneumoniae infection
- Congenital bacterial pneumonia
- Congenital chlamydial pneumonia
- Congenital pneumonia
- Neonatal chlamydial infection
- Neonatal chlamydial pneumonia
- Neonatal pneumonia
- Pneumonia caused by Chlamydia pneumoniae
- Pneumonia caused by Chlamydiaceae
Instructional NotesGuidance
Instructions from the official ICD-10-CM Tabular List that apply to P23.1: its own notes plus those printed at P23 and Chapter 16. 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.
- infective pneumonia acquired in utero or during birth
- conditions that have their origin in the fetal or perinatal period (before birth through the first 28 days after birth) even if morbidity occurs later
Excludes1
Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.
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.
Notes
General instructions on how these codes are used.
- Codes from this chapter are for use on newborn records only, never on maternal records
Source: CMS ICD-10-CM Tabular List. How to read instructional notes.
Referenced in Other NotesGuidance
Instructional notes printed at other codes that name P23.1, its category, or a range that includes it.
Excludes1 4
These codes carry an Excludes1 note naming P23.1: they are not reported together with it, unless the two conditions are unrelated.
- A56 Other sexually transmitted chlamydial diseasesneonatal chlamydial pneumonia (P23.1)
- A74 Other diseases caused by chlamydiaeneonatal chlamydial pneumonia (P23.1)
- J15 Bacterial pneumonia, not elsewhere classifiedcongenital pneumonia (P23.-) names P23.-, which includes this code
- J16 Pneumonia due to other infectious organisms, not elsewhere classifiedcongenital pneumonia (P23.-) names P23.-, which includes this code
Excludes2 1
These codes carry an Excludes2 note naming P23.1: its condition is not part of those codes, and both may be reported when the patient has both.
- Block P35-P39 Infections specific to the perinatal periodcongenital pneumonia (P23.-) names P23.-, which includes this code
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.
Patient EducationClinical
Chlamydia Infections
Chlamydia is a common sexually transmitted infection (STI). It is caused by bacteria called Chlamydia trachomatis. Anyone can get chlamydia. It often doesn't cause symptoms, so people may not know that they have it. Antibiotics can cure it. But if it's not treated, chlamydia can cause serious health problems.
The full article covers:
- What is chlamydia?
- How is chlamydia spread?
- Who is more likely to get chlamydia?
- What are the symptoms of chlamydia?
- How is chlamydia diagnosed?
- Who should be tested for chlamydia?
- What other problems can chlamydia cause?
- What are the treatments for chlamydia?
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert P23.1 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About P23.1Overview
What is the ICD-10 code for congenital pneumonia due to Chlamydia?
The ICD-10-CM code for congenital pneumonia due to Chlamydia is P23.1 (sometimes written as P231). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
Is P23.1 (Congenital pneumonia) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report congenital pneumonia due to Chlamydia on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
What MS-DRG does P23.1 group to?
When congenital pneumonia due to Chlamydia is the principal diagnosis on an inpatient stay, it groups to MS-DRG 793, 791, with relative weights from 4.1073 to 4.2192 depending on complications. Higher weights mean higher Medicare reimbursement.
Is P23.1 a CC or MCC?
CMS lists P23.1 as an MCC (major complication or comorbidity) for FY 2027. Reported as a secondary diagnosis, it places the inpatient stay in the highest-weighted DRG of its severity family. It does not count when the principal diagnosis is one of the 68 closely related codes in its exclusion list.
Can P23.1 be reported with a code from P24?
Not as a rule. The Excludes1 note at P23, which applies to P23.1, lists "neonatal pneumonia resulting from aspiration (P24.-)". 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).
