The flu season is in full swing in the U.S. and the latest Centers for Disease Control and Prevention (CDC) report, flu activity is continuing to increase. According to Vox, physicians’ offices and clinics are “bursting at the seams” because of flu. Immunization is the most effective way to prevent influenza illness and its complications and we had reported on the flu vaccine codes for the 2017-2018 season. Medical coding companies and clinicians also need to know how to assign the right ICD-10 codes for influenza.

Flu symptoms in 2018 include: fever, feverish chills, cough, sore throat, runny/stuffy nose, muscle or body aches, headaches and fatigue. According to the CDC, the flu can also cause vomiting and diarrhea in children. Influenza can cause deadly bacterial infections, such as pneumonia and exacerbate already existing chronic conditions among older adults, and even prove fatal. Influenza is caused by three types of virus – A, B, and C. Types A and B are usually responsible for seasonal epidemics in the United States, whereas type C causes mild respiratory illness and not epidemics, according to the Centers for Disease Control and Prevention. TIME reported that 30 influenza-related deaths in children this flu season were likely caused by the severe H3N2 virus.

Medical coding service providers can assign the right ICD-10 codes only if clinicians document the type and manifestations of the virus. Let’s look at the ICD-10 codes to report influenza and associated symptoms and conditions.
Right ICD-10 Codes to Report Influenza and Pneumonia in 2018

ICD-10 Codes for Influenza and pneumonia

Excludes 2: allergic or eosinophilic pneumonia (J82) aspiration pneumonia NOS (J69.0) meconium pneumonia (P24.01) neonatal aspiration pneumonia (P24.-) pneumonia due to solids and liquids (J69.-) congenital pneumonia (P23.9) lipid pneumonia (J69.1) rheumatic pneumonia (I00) ventilator associated pneumonia (J95.851)

  • J09 Influenza due to certain identified influenza viruses
  • J10 Influenza due to other identified influenza virus
  • J11 Influenza due to unidentified influenza virus
  • J12 Viral pneumonia, not elsewhere classified
  • J13 Pneumonia due to Streptococcus pneumoniae
  • J14 Pneumonia due to Hemophilus influenzae
  • J15 Bacterial pneumonia, not elsewhere classified
  • J16 Pneumonia due to other infectious organisms, not elsewhere classified
  • J17 Pneumonia in diseases classified elsewhere
  • J18 Pneumonia, unspecified organism

Here are the details of the key codes in this set:

  • J09 Influenza due to certain identified influenza viruses
    Excludes 1: influenza due to other identified influenza virus (J10.-) influenza due to unidentified influenza virus (J11.-) seasonal influenza due to other identified influenza virus (J10.-) seasonal influenza due to unidentified influenza virus (J11.-)

    • J09.X1 Influenza due to identified novel influenza A virus with pneumonia
      Inclusion Terms: Avian influenza; Bird influenza; Influenza A/H5N1; Influenza of other animal origin, not bird or swine; Swine influenza virus (viruses that normally cause infections in pigs).
      Note: For J09.X1, it would be necessary to code also, if applicable, for associated lung abscess (J85.1) other specified type of pneumonia.
    • J09.X2 Influenza due to identified novel influenza A virus with other respiratory manifestations
      Inclusion Terms: Influenza due to identified novel influenza A virus NOS; Influenza due to identified novel influenza A virus with laryngitis; Influenza due to identified novel influenza A virus with pharyngitis; Influenza due to identified novel influenza A virus with upper respiratory symptoms;
    • J09.X3 Influenza due to identified novel influenza A virus with gastrointestinal manifestations
      Excludes 1: ‘intestinal fu’ [viral gastroenteritis] (A08.-)
    • J09.X9 Influenza due to identified novel influenza A virus with other manifestations
      Inclusion Terms: Influenza due to identified novel influenza A virus with encephalopathy; Influenza due to identified novel influenza A virus with myocarditis; Influenza due to identified novel influenza A virus with otitis media
  • J10 Influenza due to other identified influenza virus
    Excludes 1: influenza due to avian influenza virus (J09.X-); influenza due to swine fu (J09.X-); influenza due to unidentified influenza virus (J11.-)
    If applicable, code also: associated lung abscess (J85.1)

    • J10.00 Influenza due to other identified influenza virus with unspecified type of pneumonia
    • J10.01 Influenza due to other identified influenza virus with the same other identified influenza virus pneumonia
    • J10.08 Influenza due to other identified influenza virus with other specified pneumonia
    • J10.1 Influenza due to other identified influenza virus with other respiratory manifestations
      Inclusion Terms: Influenza due to other identified influenza virus NOS Influenza due to other identified influenza virus with laryngitis Influenza due to other identified influenza virus with pharyngitis Influenza due to other identified influenza virus with upper respiratory symptoms
    • J10.2 Influenza due to other identified influenza virus with gastrointestinal manifestations
      Inclusion Terms: Influenza due to other identified influenza virus gastroenteritis
      Excludes 1: intestinal flu’ [viral gastroenteritis] (A08.-)
    • J10.8 Influenza due to other identified influenza virus with other manifestations
      • J10.81 Influenza due to other identified influenza virus with encephalopathy
      • J10.82 Influenza due to other identified influenza virus with myocarditis
      • J10.83 Influenza due to other identified influenza virus with otitis
  • J11 Influenza due to unidentified influenza virus
    • J11.0 Influenza due to unidentified influenza virus
      • J11.00 Influenza due to unidentified influenza virus with unspecified type of pneumonia
        Inclusion Terms: Influenza with pneumonia NOS
      • J11.08 Influenza due to unidentified influenza virus with specified pneumonia
        Also code: other specified type of pneumonia.
    • J11.1 Influenza due to unidentified influenza virus with other respiratory manifestations
      Inclusion Terms: Influenza NOS; Influenza laryngitis NOS; Influenza pharyngitis NOS; Influenza with upper respiratory symptoms NOS
    • J11.2 Influenza due to unidentified influenza virus with gastrointestinal manifestations
      Inclusion Terms: Influenza gastroenteritis NOS
      Excludes 1: ‘intestinal fu’ [viral gastroenteritis] (A08.-)
    • J11.8 Influenza due to unidentified influenza virus with other manifestations
      • J11.81 Influenza due to unidentified influenza virus with encephalopathy
        Inclusion terms: Influenza encephalopathy NOS
      • J11.82 Influenza due to unidentified influenza virus with myocarditis
        Inclusion terms: Influenza myocarditis NOS
      • J11.83 Influenza due to unidentified influenza virus with otitis media Inclusion terms: Influenza otitis media NOS
      • J11.89 Influenza due to unidentified influenza virus with other manifestations
  • J12 Viral pneumonia, not elsewhere classifiedFirst code: associated influenza, if applicable (J09.X1, J10.0-, J11.0-)
    Also code: associated abscess, if applicable (J85.1)
    Includes: bronchopneumonia due to viruses other than influenza viruses aspiration pneumonia due to anesthesia during labor and delivery (O74.0)
    Excludes 1: aspiration pneumonia due to anesthesia during pregnancy (O29); aspiration pneumonia due to anesthesia during puerperium (O89.0); aspiration pneumonia due to solids and liquids (J69.-); aspiration pneumonia NOS (J69.0); congenital pneumonia (P23.0); congenital rubella pneumonitis (P35.0); interstitial pneumonia NOS (J84.9); lipid pneumonia (J69.1); neonatal aspiration pneumonia (P24.-); J12.0 Adenoviral pneumonia.

    • J12.1 Respiratory syncytial virus pneumonia
    • J12.2 Parainfluenza virus pneumonia
    • J12.3 Human metapneumovirus pneumonia
    • J12.8 Other viral pneumonia
      • J12.81 Pneumonia due to SARS-associated coronavirus
        Inclusion Terms: Severe acute respiratory syndrome NOS
      • J12.89 Other viral pneumonia
    • J12.9 Viral pneumonia, unspecified

For all of these diagnostic codes, additional codes should be used, if applicable, to identify manifestations or associated conditions.

Diagnosing influenza can be difficult as most of its symptoms such as fever, cough, and aches are similar to those of many other common illnesses. The methods generally used by healthcare providers generally include rapid influenza diagnostic tests and lab tests such as viral culture, rapid antigen testing and rapid molecular assays using reverse transcription polymerase chain reaction (PCR). With the fierce flu season and heavy influx of patients, partnering with an experienced medical coding company is a viable option to ensure accurate reporting of ICD-10 influenza and pneumonia codes.