Pulmonology Coding Alert

Look for respiratory and gastrointestinal symptoms to nail the right flu dx.

As you gear up for the arriving flu season, map in some time to understand how to report influenza using ICD-10 codes when they come into effect.

Symptoms that you will commonly see with an influenza diagnosis include fever (R50.9, Fever, unspecified) with chills, cough (R05, Cough); malaise (R53.81, Other malaise); headache (R51, Headache); nasal congestion (R09.81, Nasal congestion); and soreness of the throat (J02.9, Acute pharyngitis, unspecified).

You might also see gastrointestinal symptoms such as nausea, vomiting (R11.2, Nausea with vomiting, unspecified) and diarrhea (R19.7, Diarrhea, unspecified), although it is not found in all the cases. The findings of gastrointestinal symptoms and other respiratory symptoms are vital as they influence reporting the condition correctly, both in ICD-9 as well as ICD-10.

Your pulmonologist will arrive at a diagnosis of influenza on the basis of a through history and evaluation of the patient's signs and symptoms. If your pulmonologist suspects influenza, he will take a quick test to confirm a diagnosis of influenza using a commercial rapid diagnostic test kit. This will not only help confirm the diagnosis but will also help your pulmonologist identify the type of influenza (A, B or C).

Alternatively, your pulmonologist might only take a sample using a throat or a nasal swab and send it to the laboratory for analysis to confirm the diagnosis of influenza.

Reporting Influenza Using ICD-9 Codes

Start with 487 (Influenza caused by unspecified influenza virus) and, depending on symptoms and other manifestions, apply a 4th digit as follows:

• 487.0 -- Influenza with pneumonia (It is essential to identify the type of pneumonia using an additional code)
• 487.1 -- Influenza with other respiratory manifestations (such as laryngitis, pharyngitis or other upper respiratory infections)
• 487.8 -- Influenza with other manifestations (such as encephalopathy or gastrointestinal symptoms)

Note Gastro Symptoms and Other Manifestations in ICD-10

When ICD-10 comes into effect, 487 under ICD-9 codes will crosswalk to J10 (Influenza due to other identified influenza virus) and J11 (Influenza due to unidentified influenza virus). As with ICD-9, both J10 and J11 further expand into a fourth digit classification based on the presence or absence of pneumonia, other respiratory manifestations (such as laryngitis, pharyngitis, and upper respiratory infections), encephalopathy and gastrointestinal manifestations.

You'll identify other manifestations such as encephalopathy, otitis media or myocarditis with a fifth digit.

For example, J10 under ICD-10 expands into the following four codes using a fourth digit expansion:

• J10.0 (Influenza due to other identified influenza virus with pneumonia)
• J10.1 (Influenza due to other identified influenza virus with other respiratory manifestations)
• J10.2 (Influenza due to other identified influenza virus with gastrointestinal manifestations)
• J10.8 (Influenza due to other identified influenza virus with other manifestations)

J10.8 further expands into the following four codes using a 5th digit expansion based on the type of manifestation:

• 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 media)
• J10.89 (Influenza due to other identified influenza virus with other manifestations). Use additional code to identify the manifestation.

Red flag: Do not use the J10 series unless the physician has definitively identified the type of influenza virus. If it is not identified use the J11 series.

Editor's Note: For charts that crosswalk ICD-9 and ICD-10 codes for influenza, please email the editor, Sachin Thimmaiah, sthimmaiah@codinginstitute.com .