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ICD-10 Guide
ICD-10 CodesE66.01

E66.01

Billable

Morbid (severe) obesity due to excess calories

BILLABLE STATUSYes
IMPLEMENTATION DATEOctober 1, 2015
LAST UPDATED09/05/2025

Code Description

ICD-10 E66.01 is a billable code used to indicate a diagnosis of morbid (severe) obesity due to excess calories.

Key Diagnostic Point:

Morbid obesity, classified under ICD-10 code E66.01, is characterized by an excessive accumulation of body fat that presents a significant risk to health. This condition is typically defined by a Body Mass Index (BMI) of 40 or higher, indicating severe obesity. The primary cause of this condition is an imbalance between calorie intake and energy expenditure, often exacerbated by lifestyle factors such as poor diet, lack of physical activity, and genetic predisposition. Morbid obesity is associated with numerous health complications, including type 2 diabetes, hypertension, cardiovascular diseases, and certain types of cancer. It can also lead to psychological issues such as depression and anxiety. Effective management of morbid obesity often requires a multidisciplinary approach, including dietary modifications, physical activity, behavioral therapy, and in some cases, surgical interventions. Accurate coding of this condition is crucial for appropriate treatment planning and reimbursement.

Code Complexity Analysis

Complexity Rating: Medium

Medium Complexity

Complexity Factors

  • Need for precise BMI calculations to confirm morbid obesity status.
  • Differentiation from other obesity-related codes.
  • Documentation of comorbid conditions that may accompany obesity.
  • Understanding of lifestyle factors contributing to obesity.

Audit Risk Factors

  • Inadequate documentation of BMI measurements.
  • Failure to document lifestyle factors contributing to obesity.
  • Lack of evidence for comorbid conditions.
  • Misclassification of obesity severity.

Specialty Focus

Medical Specialties

Endocrinology

Documentation Requirements

Detailed patient history, including weight history, BMI calculations, and comorbid conditions.

Common Clinical Scenarios

Patients presenting with metabolic syndrome or type 2 diabetes related to obesity.

Billing Considerations

Endocrinologists must ensure that documentation reflects the cause of obesity and any hormonal imbalances.

Bariatric Surgery

Documentation Requirements

Comprehensive evaluation reports, including psychological assessments and pre-operative weight loss attempts.

Common Clinical Scenarios

Patients seeking surgical intervention for weight loss.

Billing Considerations

Documentation must support the medical necessity of surgery and include all relevant comorbidities.

Coding Guidelines

Inclusion Criteria

Use E66.01 When
  • According to ICD
  • 10 coding guidelines, E66
  • 01 should be used when the patient's obesity is classified as morbid and is due to excess caloric intake
  • Coders must ensure that the documentation supports the diagnosis and includes BMI measurements

Exclusion Criteria

Do NOT use E66.01 When
  • Exclusions include obesity due to other medical conditions

Related ICD-10 Codes

Related CPT Codes

43600CPT Code

Bariatric surgery

Clinical Scenario

When a patient with E66.01 undergoes surgical intervention for weight loss.

Documentation Requirements

Pre-operative assessments, BMI documentation, and justification for surgery.

Specialty Considerations

Bariatric surgeons must ensure that all documentation supports the medical necessity of the procedure.

ICD-10 Impact

Diagnostic & Documentation Impact

Enhanced Specificity

ICD-10 Improvements

The transition to ICD-10 has allowed for more specific coding of obesity-related conditions, improving the accuracy of diagnoses and treatment plans. E66.01 provides a clear distinction for morbid obesity due to excess calories, facilitating better patient management and reimbursement processes.

ICD-9 vs ICD-10

The transition to ICD-10 has allowed for more specific coding of obesity-related conditions, improving the accuracy of diagnoses and treatment plans. E66.01 provides a clear distinction for morbid obesity due to excess calories, facilitating better patient management and reimbursement processes.

Reimbursement & Billing Impact

reimbursement processes.

Resources

Clinical References

  • •
    Obesity Management Resources

Coding & Billing References

  • •
    Obesity Management Resources

Frequently Asked Questions

What is the difference between E66.01 and E66.09?

E66.01 is specifically for morbid obesity due to excess calories, while E66.09 is used for other types of obesity that do not fall under this category. Accurate documentation is essential to determine the correct code.