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Internal Medicine Coding Alert


BMI Coding: Becoming More Specific Under ICD-10

Most ICD-9 codes have straight crosswalk for ICD-10.

Obesity in adults and children continues to be a hot topic in the news, and a common condition for family physicians to see in their practices. Documentation associated with body mass index (BMI) will continue to need great detail when ICD-10 becomes effective in October 2014, because of numerous code choices.

Current options: ICD-9 divides BMI diagnoses into several choices under code family V85 (Body mass index). The primary options are:

1.       V85.0 – Body mass index less than 19, adult

2.       V85.1 – Body mass index between 19-24, adult

3.       V85.2x – Body mass index between 25-29, adult

4.       V85.3x – Body mass index between 30-39, adult

5.       V85.4x – Body mass index 40 and over, adult

6.       V85.5x – Body mass index, pediatric.

Further sub-classifications are used for the fifth digit of codes V85.2x, V85.3x, V85.4x, and V85.5x. For example, the choices under V85.2x are as follows:

·         V85.21 – Body mass index 25.0-25.9, adult

·         V85.22 – Body mass index 26.0-26.9, adult

·         V85.23 – Body mass index 27.0-27.9, adult

·         V85.24 – Body mass index 28.0-28.9, adult

·         V85.25 – Body mass index 29.0-29.9, adult.

ICD-10 differences: The only changes when you begin using ICD-10 will be where the codes break (for instance, “less than 19” versus “19 or less”), and that more specific BMI incremental reporting begins with BMI 20 in ICD-10, as opposed to BMI 25 in ICD-9.

Here’s the crosswalk breakdown:

·         V85.0 converts to Z68.1 (Body mass index [BMI] 19 or less, adult) (note BMI 19 exception).

·         V85.1 (with the exception of those who have a BMI of 19) and V85.21 through V85.25 crosswalk to 10 codes in ICD-10: Z68.20 (Body mass index [BMI] 20.0-20.9, adult) through Z68.29 (Body mass index [BMI] 29.0-29.9, adult)

·         V85.30 (Body Mass Index 30.0-30.9, adult) through V85.39 (Body Mass Index 39.0-39.9, adult) crosswalk directly to Z68.30 (Body mass index [BMI] 30.0-30.9, adult) through Z68.39 (Body mass index [BMI] 39.0-39.9, adult)

·         V85.41 through V85.45 crosswalk directly to Z68.41 (Body mass index [BMI] 40.0-44.9, adult) through Z68.45 (Body mass index [BMI] 70 or greater, adult)

·         V85.5x converts to Z68.5_ (Body mass index [BMI], pediatric…).

Also note: Like V85.5x in ICD-9, the fifth character options for Z68.5_ are: 1 (. . . less than 5th percentile for age), 2 (. . . 5th percentile to less than 85th percentile for age), 3 (. . . 85th percentile to less than 95th percentile for age), and 4 (. . . greater than or equal to 95th percentile for age). Further, both ICD-9 and ICD-10 define “pediatric” for purposes of BMI as people age 2-20 years old; the adult codes are for people over 20 years old. Finally, the ICD-10 guidelines, like those in ICD-9, state that the BMI codes should only be reported as secondary diagnoses and that, as with all other secondary diagnosis codes, the BMI codes should only be assigned when they meet the definition of a reportable additional diagnosis.

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