MUE, MAI, and you

By Alexander Miller, MD, June 3, 2019

A Medicare-insured patient travels some distance from his rural home to see you about several recurrently bleeding skin lesions. You identify six individual lesions suspicious for infiltrating to morpheaform basal cell carcinomas. Since the patient traveled far to your office, you offer to biopsy all six of the lesions on the same day. You do six individual punch biopsies, each on a separately identifiable lesion, and report the biopsies with CPT code 11104 and 11105 code X 5. Your Medicare Administrative Contractor (MAC) adjudicates the claim and denies payment for some of the biopsies. What happened? All the biopsies were medically reasonable and necessary.

The answer hinges upon the Centers for Medicare and Medicaid Services (CMS) Medically Unlikely Edits (MUE) table. MUEs exist to reduce Medicare Part B claims payment errors. The MUE table lists the maximum unit(s) of a specified CPT/HCPS code that would typically be reported for services done on one patient, on one day. Most CPT codes that are assigned MUEs are published by CMS. These can be found at www.cms.gov/medicare/coding/nationalcorrectcodinited/mue.html. Some MUEs are not published and are not made public. This is intended to guard against abuse. Fortunately, MUEs for codes used by dermatologists are nearly all published and readily accessible. Knowing the MUEs will allow one to either stay within the MUE parameters when providing services or to be prepared for a claim denial and subsequent appeal.

Let’s return to the six punch biopsies billing scenario discussed above. All biopsies were of separately identifiable lesions, and all were medically necessary. What does the MUE table tell us?

CPT code 11104, punch biopsy, has an MUE of 1. That makes sense, as the code describes a single lesion punch biopsy procedure. There can only be one single lesion. Separate/additional punch biopsies are reported with CPT code 11105. The MUE table limits additional punch biopsies to three. That means that whenever one does more than four punch biopsies in one day on the same patient, your MAC is not likely to cover the entire service even if it is totally reasonable and necessary. By now you must have noticed the MUE Adjudication Indicator column along with the MUE Rationale column. What are those?

MUE Adjudication Indicators (MAI) specify three types of claims adjudication parameters, identified by numbers 1, 2, or 3. A MAI of 1 is a claim line edit, which means that each reported service is adjudicated as a claim line edit. This type of edit facilitates a simple billing bypass of the MUE edit limits by reporting services that exceed an MUE on a separate claim line. For example, if a service has an MUE of 3, but you perform four units of the service, you could report three units of the service on the first line of the claim and an additional unit of the same service on a subsequent line of the claim. This approach would bypass the MUE edit and the claim would be adjudicated and would pay for all four units of the service. Realizing that this could change the intent of the MUE values, CMS has transitioned the majority of MUEs to MAIs of 2 or 3.

MAIs of 2 are date-of-service edits that are absolute, based upon policy, such as CPT code definitions. For example, skin biopsy codes 11102, 11104, 11106 all have MAIs of 2. The rationale for this MAI is described in the MUE Rationale column of the MUE table. In this case, the reasoning is straightforward: all three of these codes are limited to the first (single) biopsy. As there can only be one first biopsy of a given type, each of the biopsy codes carries an MAI of 2. Similarly, CPT code 17000, destruction of premalignant lesions, also has a MAI of 2, as there can only be one “first lesion” destruction.

MAIs of 3 specify date-of-service edits, meaning “per day.” For example, additional tangential biopsies, CPT code 11103, have an MUE of 6 and MAI of 3. This means that in addition to the first tangential biopsy, CPT code 11102, one may do six additional biopsies on separately identifiable lesions on the same day, report them for that date of service, and be eligible for payment by the MAC. Any additional tangential biopsies beyond seven done on one day on a given patient will not be payable, regardless of whether the services are reported on one claim line or multiple claim lines. MAIs of 3 are generated based upon “clinical benchmarks.”

CMS realizes that there may be reasonable clinical instances where one may exceed the MUE for services that have MAIs of 3. Consequently, one may appeal reasonable and necessary services that are automatically denied based upon MUEs with MAIs of 3. Such appeals may be done via claims reopening or redetermination.

Example 1: You suspect that your service billable to Medicare will exceed its MUE value. You have your patient sign an Advanced Beneficiary Notice of Noncoverage (ABN) prior to performing your service, in order to assure payment for any portion of the service in excess of the MUE.

Answer: Incorrect. CMS points out that denials of payment based upon MUEs are coding policy denials rather than medical necessity/non-covered services denials. ABNs are intended for use when a service may be denied based upon a lack of medical necessity. When a denial is based upon coding parameters, an ABN will not shift the payment liability to the patient. Conclusion: ABN or not, when a payment denial is based upon incorrect coding or MUE parameters, the patient is not liable for payment.

Example 2: You punch biopsied six separately identifiable lesions on a Medicare patient and submitted a claim as follows:
11104
11105 X 5
You receive payment from your MAC for the first biopsy. All five of the rest are denied with the following explanations: CO (contractual obligation) and N362 and MA01, indicating that the units of service on the claim line exceeded the MUE number.

Answer: Correct. The total MUE for punch biopsies is 4, so you would have expected three out of five 11105 units to have been reimbursed. Not so. CMS policy is that when a claim line’s units of service exceed the MUE, the entire claim line is denied. When your units of service exceed the MUE, it is best to partition that service line and bill the excess units on separate claim lines. Four of the six punch biopsy codes would have likely been adjudicated as payable if the claim were submitted as follows:
11104
11105 X 3
11105-76 X 2
Check with your private payers on their policy for the use of modifier 76 when the same exact procedure is reported on a separate line of the same claim.

Example 3: You do four incisional biopsies on four distinct lesions located on anatomically separate body areas. You report the biopsies as:
11106
11107x2
11107-76 X1
You list diagnosis D48.5, neoplasm of uncertain behavior, for each of the biopsies and in the notes specify the distinct location of each biopsy.

Answer: Correct. Separating the excess biopsy MUE unit on its own billing line might prevent a total claim denial. Line billing, as opposed to billing as: 11106, 11107X3, will maximize optimal claim adjudication for a Medicare-insured patient, since each line will be adjudicated individually. (See Example 2.) Since the MUE for incisional biopsies is 3, the fourth biopsy may be denied and would need to be appealed to the insurer. For correct coding, the additional incisional biopsy billed on the separate line will require appending modifier 76, for Medicare claims. This prevents CPT code 11107 from being viewed as a duplicate claim line and denied on that basis.

Check with your private payers on their policy for the use of modifier 76 when the same exact procedure is reported on a separate line of the same claim.

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