2025 ICD-10-CM Diagnosis Code I33.9

Acute and subacute endocarditis, unspecified

I33.9 is a billable/specific ICD-10-CM code that can be used to indicate a diagnosis for reimbursement purposes.
The 2025 edition of ICD-10-CM I33.9 became effective on October 1, 2024.
This is the American ICD-10-CM version of I33.9 – other international versions of ICD-10 I33.9 may differ.

Applicable To

The following code(s) above I33.9 contain annotation back-references

that may be applicable to I33.9:

Approximate Synonyms

Clinical Information

Acute inflammation of the endocardium. Bacteria is the usual etiologic agent, and the distinction between “acute” and “subacute” has traditionally been made based on the pathogenic organism and clinical presentation.

ICD-10-CM I33.9 is grouped within Diagnostic Related Group(s) (MS-DRG v42.0):

Convert I33.9 to ICD-9-CMCode History

2016 (effective 10/1/2015): New code (first year of non-draft ICD-10-CM)
2017 (effective 10/1/2016): No change
2018 (effective 10/1/2017): No change
2019 (effective 10/1/2018): No change
2020 (effective 10/1/2019): No change
2021 (effective 10/1/2020): No change
2022 (effective 10/1/2021): No change
2023 (effective 10/1/2022): No change
2024 (effective 10/1/2023): No change
2025 (effective 10/1/2024): No change

Diagnosis Index entries containing back-references to I33.9: