2027 ICD-10-CM Diagnosis Code J16.0Chlamydial pneumonia
ICD-10-CM Codes›J00–J99›J09-J18›J16
- Billable — Valid for Submission
- MCC — Major Complication or Comorbidity
- Not Chronic
J16.0 is a billable ICD-10-CM diagnosis code for chlamydial pneumonia. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 193 through 195, 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 129 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 and Pneumonia (except that caused by tuberculosis).
Code Identity
Code Classification
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Chlamydia pneumoniae infection
- Pneumonia caused by Chlamydia pneumoniae
- Pneumonia caused by Chlamydiaceae
Instructional NotesGuidance
Instructions from the official ICD-10-CM Tabular List that apply to J16.0: its own notes plus those printed at J16, block J09-J18, and Chapter 10. A note printed at a category, block or chapter applies to every code under it.
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.
- certain conditions originating in the perinatal period (P04-P96)
- certain infectious and parasitic diseases (A00-B99)
- complications of pregnancy, childbirth and the puerperium (O00-O9A)
- congenital malformations, deformations and chromosomal abnormalities (Q00-Q99)
- endocrine, nutritional and metabolic diseases (E00-E88)
- injury, poisoning and certain other consequences of external causes (S00-T88)
- neoplasms (C00-D49)
- smoke inhalation (T59.81-)
- symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)
Code First
The underlying condition named in the note is sequenced before this code.
Use Additional Code
Add a second code, after this one, to fully describe the condition.
- code, if applicable, to identify resistance to antimicrobial drugs (Z16.-)
Code Also
A second code may be needed to fully describe the condition; the note gives no sequencing direction.
Notes
General instructions on how these codes are used.
- When a respiratory condition is described as occurring in more than one site and is not specifically indexed, it should be classified to the lower anatomic site (e.g. tracheobronchitis to bronchitis in J40).
Source: CMS ICD-10-CM Tabular List. How to read instructional notes.
Referenced in Other NotesGuidance
Instructional notes printed at other codes that name J16.0, its category, or a range that includes it.
Excludes1 2
These codes carry an Excludes1 note naming J16.0: they are not reported together with it, unless the two conditions are unrelated.
Excludes2 1
These codes carry an Excludes2 note naming J16.0: its condition is not part of those codes, and both may be reported when the patient has both.
- A74 Other diseases caused by chlamydiaechlamydial pneumonia (J16.0)
Use Additional Code 1
These codes say to use an additional code from the note, and J16.0 is one of the codes named.
- J95.89 Other postprocedural complications and disorders of respiratory system, not elsewhere classified
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.
Clinical InformationClinical
Chlamydial Pneumonia
pneumonia caused by infections with the genus chlamydia; and chlamydophila, usually with chlamydophila pneumoniae.
Patient EducationClinical
Pneumonia
Pneumonia is an infection in one or both of your lungs. It causes the air sacs of your lungs to fill up with fluid or pus. Pneumonia can range from mild to severe, depending on what caused it, your age, and your overall health.
The full article covers:
- What is pneumonia?
- What causes pneumonia?
- Who is more likely to develop pneumonia?
- What are the symptoms of pneumonia?
- What other problems can pneumonia cause?
- How is pneumonia diagnosed?
- What are the treatments for pneumonia?
- Can pneumonia be prevented?
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert J16.0 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About J16.0Overview
What is the ICD-10 code for chlamydial pneumonia?
The ICD-10-CM code for chlamydial pneumonia is J16.0 (sometimes written as J160). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
Is J16.0 a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report chlamydial pneumonia on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
What MS-DRG does J16.0 group to?
When chlamydial pneumonia is the principal diagnosis on an inpatient stay, it groups to MS-DRG 195, 793, 791, 193, 194, with relative weights from 0.6062 to 4.2192 depending on complications. Higher weights mean higher Medicare reimbursement.
Is J16.0 a CC or MCC?
CMS lists J16.0 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 129 closely related codes in its exclusion list.
Can J16.0 be reported with a code from P23?
Not as a rule. The Excludes1 note at J16, which applies to J16.0, lists "congenital pneumonia (P23.-)". 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).
