The Impact of Using Modifier 91 and Modifier 59 on Medical Billing and Reimbursement

For holistic and integrative healthcare providers, billing errors can lead to lost revenue and denied claims. Two modifiers often misunderstood in this space Modifier 91 and Modifier 59 can make or break your reimbursement strategy. Understanding when and how to use them can help you bill more accurately and get paid for the services you’re providing.

What Is Modifier 91?

Modifier 91 is used to report repeated laboratory tests performed on the same day for the same patient, when those tests are necessary to monitor the patient’s condition. This modifier allows practices to bill for medically necessary repetitions of the same test without triggering payer denials for duplication.

If a patient undergoes glucose testing at multiple times during the day due to fluctuating blood sugar levels, each test if medically justified can be billed with Modifier 91.

Modifier 91 Billing Guidelines:

• Use only for lab tests, not procedures.

• The test must be repeated to get new results not due to errors or quality control re-runs.

• Do not apply if a different test or methodology is used.

• Documentation should clearly explain why the test was repeated.

When to Use Modifier 59

Modifier 59 is used to identify procedures or services that are not typically reported together but are appropriate under specific circumstances. It’s a way to show that services were performed independently even if the CPT codes normally bundle.

For instance, if a provider performs manual therapy on the lumbar spine and therapeutic exercises on the shoulder during the same session, Modifier 59 may be needed to demonstrate that these were distinct services and should be reimbursed separately.

Appropriate Usage of Modifier 59:

• Only when no better descriptive modifier is available.

• When procedures are performed in separate sessions or on different anatomical areas.

• Documentation must clearly support the separate and distinct nature of each service.

• Should not be used simply to bypass payer bundling edits.

The Difference Between Modifier 91 and 59

These modifiers serve very different purposes and are not interchangeable. Modifier 91 is focused on repeated lab tests, while Modifier 59 addresses distinct procedural services.

Misusing either can delay reimbursement and increase audit risk.

Modifier 91 vs Modifier 59: Examples

Modifier 91 Example:
An integrative medicine provider orders multiple cortisol tests throughout the day to monitor stress hormone fluctuations. Since the same lab test is repeated for diagnostic monitoring, Modifier 91 is added to the second test.

Modifier 59 Example:
A chiropractor provides therapeutic exercise to strengthen the shoulder and manual therapy to relieve lower back tension during a single visit. Since the procedures address different body areas, Modifier 59 is used to support separate billing.

Improve Claims Accuracy and Get Paid Faster

Using the wrong modifier or applying the right one incorrectly can result in denied claims and lost revenue. Healthcare providers should be cautious, especially when handling repeat services or combined procedures. Staying current on payer guidelines and integrating coding with Modifier 91 and 59 into your compliance process is key.

Work with Experts Who Understand Your Practice

Holistic and integrative providers often deliver care that doesn’t fit neatly into standard billing models. That’s why working with professionals who understand modifier 91 for repeated lab tests and modifier 59 for distinct procedures can make all the difference.

At Holistic Billing Services, we specialize in helping alternative health practices streamline revenue cycle management with accuracy and transparency.

👉 Talk to our billing team today and make every claim count.