Pediatric Coding Alert

Question: Can I use the equation for calculating adult body mass index (BMI) — (weight in pounds x 703 divided by height in inches) — to determine a child’s BMI?

Michigan Subscriber

Answer: Although adult BMIs are calculated with an equation, which uses either metric measurements — (weight in kilograms) divided by (height in meters, squared) — or standard measurements, as you described, pediatric BMIs are tied to percentiles of their respective age and sex.

For example, a “normal” BMI for a 4-year-old boy would be different than a 7-year-old girl, even if the BMI number itself is the same. If you don’t want to do the math for every patient, you can use the child- and teen-specific BMI calculator provided by the Centers for Disease Control and Prevention (CDC), which incorporates the relevant percentile information. Note that BMI values are not available for children 2 or younger via this calculator.

The current ICD-10-CM codes for pediatric BMI values are:

• Z68.51 (Body mass index [BMI] pediatric, less than 5th percentile for age)
• Z68.52 (… 5th percentile to less than 85th percentile for age)
• Z68.53 (… 85th percentile to less than 95th percentile for age)
• Z68.54 (…  95th percentile for age to less than 120% of the 95th percentile for age)
• Z68.55 (… 120% of the 95th percentile for age to less than 140% of the 95th percentile for age)
• Z68.56 (… greater than or equal to 140% of the 95th percentile for age)

Rachel Dorrell, MA, MS, CPC-A, CPPM, Development Editor, AAPC