Internal Medicine Coding Alert

Hint: Use manifestations in documentation to arrive at the apt diagnosis code.

When your internist diagnoses influenza, check in patient documentation for type of influenza virus and the various manifestations as these factors influence the code that you will choose. You have more specific reporting choices with ICD-10 than you did when reporting the condition with the ICD-9 system of codes.

ICD-9: When reporting a diagnosis of influenza, you start with 487 (Influenza caused by unspecified influenza virus) and, depending on symptoms and other manifestations, apply a 4^th 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, acute upper respiratory infections)
• 487.8 -- Influenza with other manifestations (such as encephalopathy or gastrointestinal symptoms)

The 487 series is also used with seasonal influenza viruses. If you know the influenza is due to certain identified influenza viruses, you may need to look at the 488 series in ICD-9. That series is also divided into three categories, based on the 4^th digit, and each also requires a 5^th digit. The 4^th digit categories in this series are:

• 488.0x – Influenza due to identified avian influenza virus
• 488.1x – Influenza due to identified 2009 H1N1 influenza virus
• 488.8x – Influenza due to novel influenza A

The fifth digit options in each of these categories are the same, and they generally parallel the fourth digits in the 487 series, namely:

1 – with pneumonia

2 – with other respiratory manifestations

9 – with other manifestations

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), gastrointestinal manifestations, or other manifestations such as encephalopathy, myocarditis, or otitis media.

 You’ll identify other manifestations such as encephalopathy, otitis media or myocarditis, with a fifth digit. Like the 487 series in ICD-9, J10 and J11 include seasonal influenza viruses.

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)
• 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)

J10.0 further expands into the following three codes using a 5^th digit expansion based on the type of pneumonia involved:

• 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 viruspneumonia)
• J10.08 (Influenza due to other identified influenza virus with other specified pneumonia) (Code also other specified type of pneumonia)

J10.8 further expands into the following four codes using a 5^th 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. The J11 series also expands using a fourth digit expansion into four codes while J11.0 and J11.8 expand using a fifth digit expansion, similar to the expansion of J10.0 and J10.8 mentioned above.

The 488 series in ICD-9 is traceable to J09 in ICD-10. There are four codes in that category:

• J09.X1 (Influenza due to identified novel influenza A virus with pneumonia)
• J09.X2 (Influenza due to identified novel influenza A virus with other respiratory manifestations)
• J09.X3 (Influenza due to identified novel influenza A virus with gastrointestinal manifestations)
• J09.X9 (Influenza due to identified novel influenza A virus with other manifestations)

Many of the codes in the J09, J10, and J11 series require you to use an additional code or “code also,” if applicable. For example, with J10, you are to use an additional code from the B97.- series to identify the virus in question. Be sure to pay attention to these instructions, where applicable.

Brush up on Your Basics Briefly

Documentation spotlight: 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 (R11.0, Nausea), vomiting (R11.1-, Vomiting), or both (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 physician will arrive at a diagnosis of influenza on the basis of a thorough history and evaluation of the patient’s signs and symptoms. If your physician 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 him identify the type of influenza (A, B or C).

Alternatively, your internist 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.