BMI-for-Age as a Screening Measure

At a glance

Pediatric health care providers are encouraged to conduct body mass index (BMI) screening for all children and adolescents 2 years or older at least once a year. Children and adolescents are growing. As a result, their BMI values need to be expressed relative to others of the same sex and age. These values are known as BMI percentiles.

Health care provider goes over chart with father and son in a medical setting.

What to know

The American Academy of Pediatrics (AAP) Clinical Practice Guideline and the Bright Futures Guidelines recommend that pediatric health care providers conduct BMI screening for all children and adolescents 2 years or older at least once a year. Screening involves:

  • Measuring height and weight.
  • Calculating BMI.
  • Assessing BMI percentile using BMI-for-Age Growth Charts.

There are many reasons to use BMI-for-age to screen for underweight, healthy weight, overweight, obesity, and severe obesity in children and adolescents. These include:

  • Screening with this measure provides an opportunity for health care providers to talk with patients and their families about the growth of children and adolescents 2 years or older.
  • BMI-for-age is a continuous measure that can be used for all children and adolescents 2 years orolder.
  • BMI-for-age can be plotted on sex-specific growth charts. Percentile curves indicate the relative position of the patient's BMI to individuals of the same sex and age from a reference population.

Child and adolescent BMI categories and corresponding sex- and age-specific BMI percentile ranges:

BMI Category

BMI Range

Underweight

Less than the 5th percentile

Healthy Weight

5th percentile to less than the 85th percentile

Overweight

85th percentile to less than the 95th percentile

Obesity

95th percentile or greater

Severe Obesity

120% of the 95th percentile or greater, or 35 kg/m2 or greater

The AAP Clinical Practice Guideline offers an expanded definition of severe obesity:

  • Class 2 Obesity: BMI greater than or equal to 120% to less than 140% of the 95th percentile or BMI greater than or equal to 35 kg/m2 to less than 40 kg/m2
  • Class 3 Obesity: BMI greater than or equal to 140% of the 95th percentile or BMI greater than or equal to 40 kg/m2

Key Message‎

Because children and adolescents are growing, their BMI values need to be expressed relative to other children or adolescents of the same sex and age. These values are known as BMI percentiles.

Test your knowledge

  1. According to the AAP Clinical Practice Guideline and the Bright Futures Guidelines, which of the following should pediatricians and other pediatric health care providers do at least once a year for all children and adolescents 2 years or older?
    1. Measure height and weight.
    2. Calculate BMI from height and weight.
    3. Plot BMI percentile using BMI-for-Age Growth Charts.
    4. All of the above.
  2. In children and adolescents, obesity is defined as a BMI greater than or equal to the 95th percentile for age and sex.
    1. True
    2. False

See answers.A

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Content Source:
National Center for Chronic Disease Prevention and Health Promotion (NCCDPHP)
  1. Question 1: D. Annual BMI screening is recommended for children and adolescents 2 years or older for growth monitoring. Question 2: True. Obesity is defined as a BMI at or above the 95th percentile for age and sex.