Table 1.
ICD-9 Codes used to define Influenza-Like Illness (ILI)
| 079.89 | Viral infection NEC | 466 | Acute bronchitis and bronchiolitis |
| 079.99 | Viral infection NOS | 466.0 | Acute bronchitis |
| 460 | Acute nasopharyngitis | 466.1 | Acute bronchiolitis |
| 462 | Acute pharyngitis | 466.19 | Acute bronchiolitis due to other infectious organism |
| 464 | Acute laryngitis and tracheitis | 478.9 | Other and unspecified diseases of upper respiratory tract |
| 464.0 | Acute laryngitis | 480 | Viral pneumonia |
| 464.1 | Acute tracheitis | 487 | Influenza |
| 464.10 | Acute tracheitis w/o obstruction | 487.0 | Influenza with pneumonia |
| 464.2 | Acute laryngotracheitis | 487.1 | Influenza with other respiratory manifestation |
| 464.20 | Acute laryngotracheitis w/o obstruction | 487.8 | Influenza with other manifestation |
| 465 | Upper respiratory infection, multiple or unspecified sites | 490 | Bronchitis not specified as acute or chronic |
| 465.0 | Acute laryngopharyngitis | 780.6 | Fever |
| 465.8 | Upper respiratory infection of multiple sites | 784.1 | Throat pain |
| 465.9 | Upper respiratory infection of unspecified sites | 786.2 | Cough |
Adapted from Eick-Cost AA, Hunt DJ. 2015 Assessment of ICD-9-based case definitions for influenza-like illness surveillance. MSMR