ICD-10-CM 2027 diagnosis code
A70Chlamydia psittaci infections
A70 is a valid, billable ICD-10-CM code for chlamydia psittaci infections. It can be reported on claims for dates of service from October 1, 2026 – September 30, 2027.
Looking up by condition? See ICD-10 code for Ornithosis, ICD-10 code for Psittacosis.
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 A70
A70 is the ICD-10-CM diagnosis code for chlamydia psittaci infections. It belongs to block A70-A74 (other diseases caused by chlamydiae) and chapter 1 (certain infectious and parasitic diseases). It is billable, so it can be reported on its own for dates of service from October 1, 2026 through September 30, 2027.
As a secondary diagnosis it is a CC (complication or comorbidity), which can move an inpatient stay into the "with CC" 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 865 (Viral Illness with MCC, relative weight 1.3485) and DRG 866 (Viral Illness without MCC, relative weight 0.8692), in MDC 18 (Infectious and Parasitic Diseases, Systemic or Unspecified Sites), 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 073.9 (Ornithosis, unspecified).
Coding notes
- Ornithosis
- Parrot fever
- Psittacosis
Notes that apply from higher levels
Instructions written at a parent level also apply to A70.
Broader instructions also apply from A70-A74 Other diseases caused by chlamydiae and Chapter 1: Certain infectious and parasitic diseases.
Alphabetic index entries
9 entriesTerms in the official ICD-10-CM index that lead to A70.
- Chlamydia, chlamydial › psittaci (infection)
- Fever (inanition) (of unknown origin) (persistent) (with chills) (with rigor) › parrot
- Infection, infected, infective (opportunistic) › Chlamydia, chlamydial › psittaci
- Ornithosis
- Parrot fever
- Pneumonia (acute) (double) (migratory) (purulent) (septic) (unresolved) › in (due to) › ornithosis
- Pneumonia (acute) (double) (migratory) (purulent) (septic) (unresolved) › in (due to) › psittacosis
- Pneumonia (acute) (double) (migratory) (purulent) (septic) (unresolved) › psittacosis
- Psittacosis
Codes whose notes reference A70
- J16Excludes1
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 18 · Infectious and Parasitic Diseases, Systemic or Unspecified Sites
ICD-9-CM equivalent
Converter →- 073.9Ornithosis, unspecifiedapproximate
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 A70
Is A70 billable?
- Yes. A70 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can A70 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict A70 as a principal diagnosis.
Is A70 a CC or MCC?
- A70 is a CC (complication or comorbidity) under MS-DRG v44.0, unless excluded by the principal diagnosis.
What DRG does A70 group to?
- A70 is used in the MS-DRG v44.0 logic for MS-DRG 865 (Viral Illness with MCC) and MS-DRG 866 (Viral Illness without MCC). 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 A70?
- The CMS General Equivalence Mappings map A70 to ICD-9-CM 073.9.