Tired of insurance companies mistaking repeated tests as duplicates? Try using modifier 91 to overcome these denials! Little considerations, like the appropriate use of modifiers, simplify the billing process. These two-digit codes provide additional context to CPT or HCPCS codes and reduce the miscommunication between healthcare providers and payers.
Modifier 91 is one such important code. It is essential for correctly billing repeated tests performed on the same patient and day. However, it is often confused with modifier 59, which leads to several billing complications and payment issues. Let’s discuss how modifier 91 can help you collect separate reimbursements for follow-up tests.
Modifier 91 – Description
Do you know everything about modifier 91? This two-digit code specifies reevaluations. In simple words, healthcare providers use this modifier to indicate that a diagnostic laboratory was repeated on the same day and for the same patient.
To be more specific, it notifies payers that a healthcare provider performed the same test more than once to obtain subsequent results, allowing them to distinguish between original and follow-up assessments.
So, can you use it for any repetition, including equipment error or malfunction? The simple answer is no! You can only use modifier 91 when you need multiple, serial laboratory test results to treat a patient. In simple terms, when there is a medical necessity.
Modifier 91 – Examples
Want to avoid billing errors for subsequent tests? Consider the following examples to understand the correct use of modifier 91:
Potassium Monitoring
Let’s start with a simple example. Assume a 28-year-old woman with a history of hypokalemia arrives with several symptoms, such as an irregular heartbeat, nausea, and muscle cramps. The doctor performs a potassium blood test (CPT code 84132) on the patient in the morning, which reveals she has a borderline low potassium level.
Therefore, he administers intravenous (IV) potassium and orders two subsequent tests on the same day to monitor the patient’s response to the medication. As the test is repeated for medical necessity, the billing team uses modifier 91 for the follow-up assessments. The coding is as follows:
- First Test: 84132
- Second Test: 84132-91
- Third test: 84132-91
Serial Complete Blood Count (CBC) Tests
Still confused about this modifier? Let’s move on to another example! Assume a hematologist-oncologist orders serial CBC tests for a leukemia patient undergoing chemotherapy. The goal is to determine if the treatment is working.
The healthcare provider performs one test (CPT code 85025) in the morning and another later in the same day to assess and compare the blood cell counts. Since the provider repeats the Complete Blood Count (CBC) test to monitor changes in the patient’s blood cell counts and platelets, the billing team uses modifier 91 with the second test.
- First Test: 85025
- Second Test: 85025-91
Blood Glucose Monitoring of a Cardiac Patient
Suppose a 65-year-old cardiac patient with type 2 diabetes gets admitted to a hospital. To decrease potential risks, including heart attack, the doctor constantly monitors his glucose levels. He performs four blood glucose tests on the same day at regular intervals to check the patient’s condition.
The billing team bills for the first test as usual but uses modifier 91 with the three subsequent assessments.
- First Test: 82947
- Second Test: 82947-91
- Third Test: 82947-91
- Fourth Test: 82947-91
Accurate Usage Guidelines for Modifier 91
Modifier 91 can help to stop insurance companies from flagging your services as duplicates. But just like every modifier, it has its own set of rules and conditions. You cannot just apply it everywhere to receive separate payments. Let’s discuss the correct and incorrect usage of this modifier.
Appropriate Usage of Modifier 91
You should only use modifier 91 in the following scenarios.
- The same laboratory test is repeated for the same patient.
- The tests are performed at different times but on the same day.
- The reassessments are medically necessary.
- You want to obtain multiple results to observe the effectiveness of a medication or to monitor a patient’s condition.
Inappropriate Usage of Modifier 91
Avoid using modifier 91 if:
- Alternate HCPCS codes are available (they describe the series of test results. For example, glucose tolerance tests).
- The test is repeated to confirm initial test results or due to specimen mishandling or technical issues.
- The test is a part of a more comprehensive service or a panel.
Important Note: Documentation is the key to justifying the medical necessity of repeating the same test multiple times. Therefore, maintain proper records, including the reason for requiring additional data, timestamps, and all test results.
Modifier 91 vs 59 – Understanding the Difference
How often have you faced claim denials due to modifier confusion? Many healthcare providers, even billing experts, at times, find it difficult to differentiate between modifiers 91 and 59. The reason? Both modifiers provide additional information about multiple procedures performed on the same day on the same patients.
Want to avoid increased payer scrutiny and claim denials? Understand the following key differences between these two modifiers.
Purpose
Modifier 91 specifies repeated lab tests. In simple terms, it is applied when the same laboratory test is repeated multiple times on the same day for the same patient to obtain subsequent results. The primary reason? To gain a clearer picture of the patient’s health or to monitor a changing condition over time.
In contrast, modifier 59 points out distinct procedural services. To elaborate, it indicates that a procedure or service is unrelated to the other non-E/M services performed on the same day on the same patient. In short, healthcare providers use it to report those services or procedures that are not usually reported together but are appropriate under specific conditions.
Scope
Modifier 91 has a limited scope. Simply put, it is a laboratory modifier. It is only used to report repeated diagnostic lab tests. On the other hand, modifier 59 has a much broader scope. You can apply it to all distinct procedures or services, including diagnostic tests, performed on the same day as other unrelated services. These services can be performed at different locations or anatomic sites.
Limitations
As we said earlier, modifier 91 is limited to repeated laboratory tests. There is one more restriction. You can only apply this modifier if there is a medical necessity to obtain multiple test results. In simple words, you cannot use it with those assessments that are repeated to confirm initial test results or due to equipment failure.
Modifier 59 is restricted to non-E/M services, and Medicare discourages its use unless absolutely necessary. It means you can only use it if no other modifier is available to describe the situation.
Summary
By now, we hope that you can report multiple laboratory tests accurately. Modifier 91 can help you with that. This essential modifier provides clarity to insurance companies, helping them distinguish serial lab tests from duplicate services. However, it has its own criteria and restrictions.
Many providers don’t follow the accurate usage guidelines of modifier 91 and hence face financial losses. To help you overcome this problem, we have covered everything about this two-digit code in our blog, from a detailed explanation to real-world examples. So, don’t let go of any revenue opportunity. Use this modifier wherever applicable to receive fair reimbursements!
