Receiving denials for incorrectly using modifier 90? You are not the only one! Many healthcare providers experience this problem when they submit claims for services referred to an outside laboratory. The reason? Ignoring payer guidelines!
As a result, their administrative staff face extra pressure and have to spend extra time correcting errors and chasing denials. So, what is the correct way to use modifier 90? Let’s find that out. Read on to understand everything about this two-digit code, including what it means and when to apply it.
Modifier 90 Description
So, what information does this modifier convey? As per the official description, modifier 90 specifies services outsourced to a laboratory. In simple terms, this CPT modifier notifies payers that an outside laboratory performed the services based on the treating provider’s referral.
In other words, your clinic sent the specimen collected, such as a tissue, fluid, or other samples, to a reference lab for processing. The description sounds simple, right? But the trickier part is to determine who can submit a claim with this modifier. Let’s explore this a little with three specific examples.
Modifier 90 Examples
Want to understand the correct application of this modifier? Let’s start with three examples before moving to the usage guidelines.
CMP Performed by an Outside Lab
Physicians often order a comprehensive metabolic panel (CMP) to:
- Diagnose various kidney or liver conditions
- Monitor the side effects of medications
Let’s use this information to make an appropriate scenario for modifier 90. Suppose a 43-year-old diabetic patient arrives at a primary care clinic after experiencing extreme fatigue and weakness for several days. After a brief evaluation, the patient also informs the provider about his loss of appetite.
Reviewing the patient’s medical history and noting his obesity, the physician orders a comprehensive metabolic panel test and collects his blood sample. He then sends the sample to an outside pathology lab for analysis. The laboratory performs the test and bills CPT code 80053 with modifier 90.
Manual Blood Differential Referred to an Outside Lab
Let’s consider another example. We all know that different types of blood tests serve different purposes. What if you outsource a specific test (manual white blood cell differential) to an outside lab for better efficiency?
Assume a 12-year-old girl arrives at an urgent care clinic. Her parents report a high fever with swollen lymph nodes. According to them, the fever lowers in the morning but worsens by the evening. The provider performs a complete blood count (CBC) with automated differential to identify the problem. The results show abnormal white blood cell (WBC) levels.
To determine the percentage of each WBC type, the healthcare provider refers a blood differential to an outside lab. The lab performs the test manually using stained blood smears and reports the service (CPT code 85007) with modifier 90.
Comprehensive Urinalysis Performed by an Outside Lab
For our final example, suppose a 21-year-old man arrives at a primary care clinic with diabetic symptoms. He complains of excessive thirst, fatigue, and frequent need for urination. The physician evaluates the patient and orders a urinalysis for proper diagnosis.
Due to the lack of expertise and equipment, the primary care physician refers this test to an outside lab. The lab performs a comprehensive test, including both dipstick and microscopic analysis. The technician then reports this service (CPT code 81000) with modifier 90.
Accurate Usage Guidelines for Modifier 90
Still need instructions for accurately using this modifier? Follow these accurate usage guidelines:
Accurate Uses of Modifier 90
There is only one rule for using this modifier accurately! You might have referred a test or service to an outside laboratory. But only that laboratory can use this modifier to bill for its services. This brings us to the next part:
Inaccurate Use of Modifier 90
Insurance companies strongly advise physicians to avoid using this modifier for lab tests performed by an outside laboratory. Also, avoid using this two-digit code when:
- Your own lab technician or expert performed the test (in-house analysis)
- You have only collected the specimen/sample (modifier 90 is inapplicable with venipuncture codes, CPT code 36415)
- The test is part of bundled services
- The reference lab has performed anatomic pathology services
Verify Payer Rules for Modifier 90
Many insurance companies, including Anthem Blue Cross and Blue Shield, reject pass-through billing for lab services. This takes us to the point discussed in the above section: you cannot use this modifier to bill for tests that you have not performed.
Our constant advice for avoiding denials is to review and verify payer requirements about modifier 90 in advance.
Other Billing Tips for Modifier 90
Finally, follow these two additional tips to receive timely payments:
- Apply this modifier directly to the appropriate CPT code (for example, 80053-90).
- Submit complete documentation, including the test referral and reports.
Summary
We hope you now understand the accurate use of modifier 90. In case you missed anything important, let us remind you that this CPT modifier specifies lab services performed by a reference lab. If you are a treating provider, you can only charge for drawing blood or samples.
Hence, avoid pass-through billing attempts and let the performing reference lab bill for their own service with this modifier. We have discussed every detail of this two-digit code so you can understand its correct application and avoid denials.
