ICD-10-CM Code For Chlamydia Psittaci Infections: Group Overview

The International Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10-CM) code group A70 includes infections caused by Chlamydia psittaci, including psittacosis and related chlamydial respiratory or systemic infections. These ICD-10-CM diagnosis codes are used to document clinical presentations such as pneumonia, systemic involvement, or other organ manifestations resulting from Chlamydia psittaci infection, capturing disease severity and complications. Accurate coding within the ICD-10-CM A70 group supports proper claim adjudication, complete clinical documentation, and appropriate reimbursement.

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ICD-10-CM A70: Chlamydia Psittaci Infections Overview

This group represents infections caused by Chlamydia psittaci, a bacterial pathogen that primarily affects the respiratory system but can cause systemic illness. The codes capture clinical presentations such as psittacosis and related chlamydial infections. Accurate coding supports correct reimbursement by reflecting the clinical diagnosis and care complexity.

When to Use

Use a code from this group when a clinician documents infection with Chlamydia psittaci as the primary or secondary diagnosis based on clinical findings, laboratory confirmation, or epidemiologic exposure. Apply the specific code that reflects the site and severity of involvement, such as pneumonia versus systemic disease, to support accurate clinical records and billing.

ICD-10-CM Codes

1 rows

ICD-10-CM Code	Description
A70	Chlamydia psittaci infections

DRG Codes

2 rows

DRG Code	Description
865	Viral Illness with MCC
866	Viral Illness without MCC

Typical Clinical Scenarios

An adult presents to the emergency department with acute high fever, productive cough, pleuritic chest pain, and recent history of exposure to parrots at home; chest radiograph shows lobar pneumonia and laboratory testing (serology or PCR) identifies Chlamydia psittaci. This acute respiratory infection with systemic symptoms prompts assignment of a code from this group for the identified zoonotic chlamydial pneumonia. Typical codes: A70
An elderly patient with progressive dyspnea and persistent cough over several weeks after a confirmed outbreak of avian-associated respiratory illness in a nursing facility; they have comorbid chronic obstructive pulmonary disease and require hospitalization for oxygen support. Because testing confirms C. psittaci as the causative organism complicating their chronic lung disease and leading to decompensation, a code from this group is used to document the infectious process contributing to the acute exacerbation. Typical codes: A70
A patient presents to outpatient infectious disease clinic for follow-up after a recent diagnosis of psittacosis that required antibiotic therapy; they have residual fatigue and intermittent cough but no current fever, and convalescent serology demonstrates prior infection. The encounter is coded to capture the resolved but recently treated chlamydial infection for medical record continuity and public health reporting. Typical codes: A70

Related Codes

A71-TRACHOMA

ICD-10-CM Code For Trachoma: Group Overview

A74-OTHER-DISEASES-CAUSED-BY-CHLAMYDIAE

ICD-10-CM Code For Other Diseases Caused By Chlamydiae: Group Overview

Frequently Asked Questions

References

1.CPT® Codes and Descriptions. AAPC. Retrieved Aug 11, 2026.Maintains the CPT code set's official descriptions and guidelines, licensed from the American Medical Association, used as the definitional source for CPT codes on this page.
2.HCPCS Quarterly Update. Centers for Medicare & Medicaid Services (CMS). Retrieved Aug 11, 2026.CMS's quarterly release of HCPCS Level II codes and short/long descriptors, the source for HCPCS code definitions and update history.
3.ICD-10-CM Full Code List. Centers for Medicare & Medicaid Services (CMS). Retrieved Aug 11, 2026.CMS's complete ICD-10-CM diagnosis code list, used to cross-reference diagnosis codes associated with this procedure or service.

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When to Use

ICD-10-CM Codes

1 rows

ICD-10-CM Code	Description
A70	Chlamydia psittaci infections

DRG Codes

2 rows

DRG Code	Description
865	Viral Illness with MCC
866	Viral Illness without MCC

Typical Clinical Scenarios

An adult presents to the emergency department with acute high fever, productive cough, pleuritic chest pain, and recent history of exposure to parrots at home; chest radiograph shows lobar pneumonia and laboratory testing (serology or PCR) identifies Chlamydia psittaci. This acute respiratory infection with systemic symptoms prompts assignment of a code from this group for the identified zoonotic chlamydial pneumonia. Typical codes: A70
An elderly patient with progressive dyspnea and persistent cough over several weeks after a confirmed outbreak of avian-associated respiratory illness in a nursing facility; they have comorbid chronic obstructive pulmonary disease and require hospitalization for oxygen support. Because testing confirms C. psittaci as the causative organism complicating their chronic lung disease and leading to decompensation, a code from this group is used to document the infectious process contributing to the acute exacerbation. Typical codes: A70
A patient presents to outpatient infectious disease clinic for follow-up after a recent diagnosis of psittacosis that required antibiotic therapy; they have residual fatigue and intermittent cough but no current fever, and convalescent serology demonstrates prior infection. The encounter is coded to capture the resolved but recently treated chlamydial infection for medical record continuity and public health reporting. Typical codes: A70

Related Codes

A71-TRACHOMA

ICD-10-CM Code For Trachoma: Group Overview

A74-OTHER-DISEASES-CAUSED-BY-CHLAMYDIAE

ICD-10-CM Code For Other Diseases Caused By Chlamydiae: Group Overview

Frequently Asked Questions

References

1.CPT® Codes and Descriptions. AAPC. Retrieved Aug 11, 2026.Maintains the CPT code set's official descriptions and guidelines, licensed from the American Medical Association, used as the definitional source for CPT codes on this page.
2.HCPCS Quarterly Update. Centers for Medicare & Medicaid Services (CMS). Retrieved Aug 11, 2026.CMS's quarterly release of HCPCS Level II codes and short/long descriptors, the source for HCPCS code definitions and update history.
3.ICD-10-CM Full Code List. Centers for Medicare & Medicaid Services (CMS). Retrieved Aug 11, 2026.CMS's complete ICD-10-CM diagnosis code list, used to cross-reference diagnosis codes associated with this procedure or service.

Published by

Trek Health powers OpenPayer with a leading commercial payer intelligence platform, seamlessly converting fragmented payer data into actionable insights for provider organizations.

ICD-10-CM Code For Chlamydia Psittaci Infections: Group Overview

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ICD-10-CM A70: Chlamydia Psittaci Infections Overview

ICD-10-CM Code For Chlamydia Psittaci Infections: Group Overview

Sign up for ICD-10-CM Code For Chlamydia Psittaci Infections: Group Overview policy alerts

ICD-10-CM A70: Chlamydia Psittaci Infections Overview

When to Use

ICD-10-CM Codes

DRG Codes

Typical Clinical Scenarios

Related Codes

Which infections are included in the ICD-10-CM A70 group?

How is `A70` used in clinical documentation and coding?

What clinical presentations does the A70 group capture?

Which related DRGs are mentioned for Chlamydia psittaci infections?

Why is accurate coding of `A70` important for payers and providers?

References

When to Use

ICD-10-CM Codes

DRG Codes

Typical Clinical Scenarios

Related Codes

Which infections are included in the ICD-10-CM A70 group?

How is `A70` used in clinical documentation and coding?

What clinical presentations does the A70 group capture?

Which related DRGs are mentioned for Chlamydia psittaci infections?

Why is accurate coding of `A70` important for payers and providers?

References