BMI can’t stand alone

January 27th, 2020 / By Kimberly Lodge, RHIT, CCS

It is easy to get into a habit of coding diagnosis codes without contemplating the reason behind using the code. I have noticed this particularly with the utilization of the Body Mass Index (BMI) ICD-10 codes. BMI documentation is made on most physician outpatient visits, in capturing History and Physicals, and other documents within the patient’s record. When coders see the documentation is several places, they start to assume that it should be reported.

Coding Clinic has addressed this topic over the years, noting that BMI should not be coded without an associated diagnosis such as overweight or obesity. The 2018 4th Quarter Coding Clinic overrides all previous Coding Clinics and states that BMI codes are not intended for routine capture of BMI unless there is provider documentation of an associated diagnosis, such as overweight, obesity or underweight, and adding that any of these diagnoses must meet the definition of an additional diagnosis. 

According to Section III of the 2019 ICD-10-CM Official Guidelines, before you assign a secondary diagnosis, consider whether the condition meets any of the elements for affecting patient care: Does it require clinical evaluation, therapeutic treatment, diagnostic procedures, extend the length of the hospital stay or increase the nursing care or monitoring?

The coding guidelines also state that when BMI can be reported, the documentation can come from records other than the provider, such as dietitian or nursing documentation. It is also important to note that BMI codes are not to be utilized during pregnancy.

Documentation and reporting of BMI is an important piece of information when coding a complete picture of a patient’s health status. The key is remembering to include the associated diagnoses to meet documentation requirements.

Kimberly Lodge is a coding analyst for 3M Health Information Systems.