Cardiology Coding Alert

I05.2 offers a good lesson in why your superbill's font matters.

Valve disease diagnosis codes are notoriously confusing. Get a head start on mastering these diagnoses under ICD-10 with a look at how one of your ICD-9 options will change when ICD-10 goes into effect in 2013.

ICD-9-CM code: 394.2, Mitral stenosis with insufficiency

ICD-10-CM code: I05.2, Rheumatic mitral stenosis with insufficiency

Dx definition: Mitral stenosis refers to narrowing (stenosis) of the heart's mitral valve, which is situated between the left atrium and left ventricle. When the physician additionally documents insufficiency (or incompetence or regurgitation), you should consider the codes listed above. "Rheumatic" is a reference to rheumatic fever, a disease which may result in heart damage.

Rheumatic: ICD-9 code 394.2 is not specific to "rheumatic" mitral stenosis with insufficiency.

The ICD-10 descriptor for I05.2 includes the term "rheumatic," but the "includes" note under I05 (Rheumatic mitral valve disease) specifies that the range is appropriate for conditions "whether specified as rheumatic or not." So if the documentation specifies the case is rheumatic or if it doesn't mention the cause,I05.2 will be appropriate. On the other hand, if the documentation states the disease is not rheumatic, you will use a code from I34.-.

Multiple valve involvement: For 394.x (Diseases of mitral valve), ICD-9 has an excludes note telling you to instead use 396.x if the patient also has aortic valve involvement.

ICD-10 similarly instructs you to use a different code range (not I05.-) for mitral valve disease if there is aortic valve involvement. You will instead use I08.- (Multiple valve diseases). This is the same range ICD- 10 instructs you to use if the patient has tricuspid valve involvement in addition to mitral valve disease.

Documentation: To ensure you'll be able to choose the most appropriate ICD-10 code, your clinicians' documentation must indicate whether the condition is rheumatic. It also should specify whether the mitral  valve alone is involved.

When you create your ICD-10 coding tools, make the "rheumatic/nonrheumatic/unspecified" rules clear, and refer coders to I34.- for non-rheumatic cases. Similarly, highlight that I05.2 is for mitral disease only. If other valves are involved, the correct code will be found in the I08.- range.

Tip: Just like 394.2, I05.2 is appropriate for mitral stenosis with incompetence or regurgitation, so stay alert for those terms.

Is that a 1 or an I? A 0 or an O? Take care to distinguish between similar looking characters when you're assigning ICD-10 codes. Code I05.2 is an excellent example of a code that contains easily confused characters. Keep in mind that your first character is a letter and will be followed by digits. So I05.2 is the letter "I" followed by the number "0."

Remember: When ICD-10 goes into effect on Oct. 1, 2013, you should apply the code set and official guidelines in effect for the date of service reported. Learn more at www.cms.gov/ICD10/  and www.cdc.gov/nchs/icd/icd10cm.htm#10update.

And look to a future issue for an article offering further details on properly reporting valve disease diagnoses.