Medical Decision Making (MDM) plays a critical role in selecting the correct Evaluation and Management (E/M) service level. Understanding when to use MDM versus time-based coding, how preventive visits are reported, and how chronic conditions affect code selection helps healthcare providers improve documentation accuracy, maintain coding compliance, and reduce claim denials.
Can Laboratory Tests Be Counted Toward MDM During a Preventive Visit?
No. Laboratory tests and other diagnostic tests ordered during a preventive medicine service (CPT® codes 99381–99397) cannot be counted toward Medical Decision Making (MDM).
The 2021 CPT E/M guideline revisions apply only to office and outpatient Evaluation and Management codes (99202–99215) and do not affect preventive medicine services.
When Can an Additional E/M Service Be Reported?
If a provider identifies a significant new problem or manages an existing medical condition during a preventive visit, an additional problem-oriented E/M service may be reported.
This is appropriate when:
- A separate medical condition requires additional evaluation.
- The provider performs the key components of a problem-oriented E/M service.
- The documentation supports a medically necessary, separately identifiable service.
In these situations:
- Report the appropriate preventive medicine code (99381–99397).
- Report the applicable office or outpatient E/M code (99202–99215).
- Append Modifier 25 to the E/M code.
Unlike preventive services, laboratory tests and diagnostic studies ordered during the problem-oriented visit may be considered when determining the MDM level.
Determining MDM for Uncontrolled Type 2 Diabetes
Selecting the appropriate E/M level depends on the documented severity of the patient’s condition.
According to the CPT® Medical Decision Making table:
- One chronic illness with exacerbation generally supports Moderate MDM.
- One or more chronic illnesses with severe exacerbation, progression, or treatment side effects may support High MDM.
Patients with uncontrolled Type 2 diabetes mellitus (T2DM) who experience repeated hyperglycemic and hypoglycemic episodes often require complex clinical evaluation and management.
Depending on the patient’s overall condition and documentation, the encounter may support reporting:
- 99214 (Moderate level)
- 99215 (High level)
Providers should clearly document:
- Severity of diabetes
- Frequency of exacerbations
- Associated complications
- Clinical assessment
- Treatment decisions
- Medical necessity
Comprehensive documentation is essential to justify the selected E/M service level.
MDM vs. Time: Which Should Be Used?
The American Medical Association (AMA) allows providers to select office and outpatient E/M codes using either:
- Medical Decision Making (MDM), or
- Total physician or qualified healthcare professional time on the date of service.
Providers should choose the method that most accurately reflects the work performed during the encounter.
When MDM Is the Better Choice
MDM is often more appropriate when:
- The patient presents with complex medical problems.
- Clinical decision making is extensive.
- Significant diagnostic or treatment decisions are made.
- The visit is relatively short but medically complex.
When Time-Based Coding Is Appropriate
Time-based coding is appropriate when:
- The total encounter time meets CPT requirements.
- Counseling or care coordination consumes a substantial portion of the visit.
- Documentation clearly supports the total time spent and explains why additional time was medically necessary.
Simply documenting time does not require providers to bill based on time if Medical Decision Making more accurately represents the complexity of the encounter.
Documentation Tips for Accurate Medical Decision Making Coding
To support proper E/M code selection, providers should:
- Clearly document all addressed medical problems.
- Record the severity of chronic conditions and exacerbations.
- Include all relevant diagnostic tests reviewed and ordered.
- Explain clinical reasoning behind treatment decisions.
- Document total time only when billing based on time.
- Support medical necessity for every reported service.
- Use Modifier 25 appropriately when reporting preventive and problem-oriented services on the same date.
Conclusion
Accurate medical decision making and coding requires a thorough understanding of CPT® E/M guidelines, preventive service rules, and documentation standards. Whether selecting codes based on MDM or time, providers should ensure that documentation fully reflects the complexity of patient care, supports medical necessity, and complies with current coding requirements. Proper application of these principles helps improve coding accuracy, reduce audit risk, and support appropriate reimbursement.