ICD-9-CM Diagnosis Code 033.9
Diagnosis Code: 033.9 (Raw: 0339)
Description: Whooping cough, unspecified organism
Classification: International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM)
Fiscal Year: 2026 Reference
CMS Section 111 Status: Valid for reporting.
Overview & Historical Usage
ICD-9-CM code 033.9 is designated for Whooping cough, unspecified organism. While superseded by ICD-10 for current healthcare encounters, it remains a recognized reference code for CMS Section 111 reporting, legacy claims adjudication, and historical clinical data analysis.
