Home Health ICD-9/ICD-10 Alert

Know when it's safe to code obesity, and when you should list a code for BMI alone.

The 2011 ICD-9 update added greater detail to body mass index (BMI) coding. Get the latest word on how and when to list the new codes.

Get the BMI Background

A person's BMI is the measure of his body fat based on his height and weight. BMI calculations are used as a tool to estimate the range of healthy weight based on a person's height.

The National Heart Lung and Blood Institute, a division of the National Institutes of Health produced the following table clinicians can use to calculate patient BMI:

BMI less than 18.5: Underweight

BMI in the 19--"24.9 range: Normal

BMI in the 25-- 29.9 range: Overweight

BMI in the 30--"34.9 range: Obesity Class 1

BMI in the 35--"39.9 range: Obesity Class 2

BMI of 40 and above: Extreme obesity

The 2011 ICD-9 BMI codes break down as follows:

V85.0 (Body Mass Index less than 19, adult);

V85.1 (Body Mass Index between 19-24, adult);

V85.2x (Body Mass Index between 25-29, adult);

V85.3x (Body Mass Index between 30-39, adult);

V85.4x (Body Mass Index 40 and over, adult).

Note: As of Oct. 1, V85.4x gained a fifth digit, allowing you to be more specific with patients whose BMIs range from 40 to 70 and over.

With these tools in hand, it might seem a simple next step to list an additional diagnosis code to indicate a patient's obesity or underweight, but that would be a misstep.

Don't Jump to Conclusions with Obesity

While you can code for BMI based on documentation from a dietician, nurse, or other caregiver, only a physician can make the determination as to whether your patient is obese, says Joan L. Usher, BS, RHIA, COS-C, ACE, with JLU Health Record Systems in Pembroke, Mass. That goes for diagnosing a patient as underweight, too.

Example: The nurse has determined that your patient has a BMI of 45.0. You have enough information to list V85.42 (Body Mass Index 45.0-49.9, adult), but you cannot list 278.01 (Morbid obesity) without further  documentation from the physician.

On the other hand: You will notice that instructions in your coding manual at 278.0x (Overweight and obesity) and 783.2x (Abnormal loss of weight and underweight) advise you to use an additional code from the V85.x subcategory to identify Body Mass Index (BMI) if known. So, if you have physician documentation of either of these diagnoses, be sure to include the appropriate BMI code as well.