Pathology billing and CMS

Cracking the Code

Alexander Miller

Dr. Miller, who is in private practice in Yorba Linda, California, represents the American Academy of Dermatology on the AMA-CPT Advisory Committee.

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During the course of Mohs surgery for an excision of a lentigo maligna on a Medicare patient’s face you have a melan-A (MART-1) stain done to assess junctional melanocytic proliferation. You bill with the CPT code 88342, “Immunohistochemistry or immunocytochemistry, each separately identifiable antibody per block, cytologic preparation, or hematologic smear; first separately identifiable antibody per slide,” which has been revised for 2014. That is correct CPT coding, and you expect to be paid. Will you be paid?

Seems that in the above scenario proper CPT coding guidelines were followed. However, when dealing with Medicare, occasionally peculiar billing regulations will surface. Such is the case with 2014 CPT codes 88342, as quoted above, and 88343, “each additional separately identifiable antibody per slide (list separately in addition to code for primary procedure).”

As of Jan. 1, 2014 the Centers for Medicare and Medicaid Services (CMS) has decreed that CPT codes 88342 and 88343 are “not valid for Medicare purposes” and CMS will deny payment for these codes. Two new HCPCS Level II codes have been created to substitute for 88342 and 88343. These new codes must be used to qualify immunohistochemistry billing for reimbursement. The new HCPCS codes, to be used without a modifier when billing for the global service or with an appropriate 26 professional services or TC technical component service modifier, are:

  • G0461 Immunohistochemistry or immunocytochemistry, per specimen; first single or multiplex antibody stain
  • G0462 each additional single or multiplex antibody stain (List separately in addition to code for primary procedure)

Consequently, the melan-A stain done in one’s Mohs lab and interpreted on site would be coded to your Medicare Administrative Contractor as G0461. [pagebreak]

Multiple individual stains applied separately to tissue slides would be coded individually per immunoperoxidase stain. For example, if a spindle cell tumor were individually stained with S-100, pancytokeratin, and vimentin, each stain would be billed individually as follows:

  • G0461 for the first stain
  • G0462 x2, for the second and third individual stains

Note that if a cocktail of immunoperoxidase stains such as pan melanoma plus S-100 (a multiplex antibody stain) is applied to a single specimen, regardless of the number of antibodies contained and stained for in the cocktail, one bills only one unit of G0461. Each separately identifiable additional cocktail would engender an additional G0462 add-on code. Additionally, the unit of service for code 88342 is the first antibody applied to a slide derived from a block of tissue, whereas the service unit for G0461 is the first stain applied to tissue from an entire tissue specimen.

You and your billers will need to remain vigilant as to the entity being billed for immunohistochemical services: a private insurer or Medicare. Private insurers should be billed following CPT code guidelines and Medicare bills should call for the appropriate HCPCS Level II codes. However, billing conventions may vary from one insurance plan to another, so it is imperative to keep track of which coding convention a plan seems to prefer and to bill accordingly with the plan-preferred CPT or G codes.

General information as well as access to the entire 2014 HCPCS Level II code set is available on the CMS website at [pagebreak]

Documenting lab requests

Now, on to another, more universal, pathology billing and reimbursement matter. Histopathology interpretation services are laboratory services that require, per Medicare guidelines, documentation in the patient medical record indicating a request for the laboratory service. This order may be in the form of a signed requisition, a copy of which is retained in the patient’s record, or a clear documentation in the patient record that the test is to be done. Lack of such documentation may cause a denial of payment for the pathology laboratory service or, in an audit situation, lead to a refund demand. Chart documentation should also support the “reasonable and necessary” nature of the requested testing. The generated report must then be either hand or electronically signed by the physician producing the report.

The clinical laboratory request regulations are spelled out in the Medicare Benefit Policy Manual, Chapter 15, Section 80.6, available on the CMS website.

A request for histopathology testing must be appropriately documented. In an audit situation, the testing laboratory would have to prove that a legitimate request for the billed services exists. The easiest way to do this is for the laboratory to submit copies of signed histopathology testing requisitions. In the absence of signed requisitions, documentation of the laboratory testing order would have to be sought from the patient record. In an audit, it is the laboratory’s burden to provide adequate evidence of test orders. One can readily appreciate how cumbersome the process can become when signed testing orders are not available to the audited laboratory. The penalties in the form of refund requests and/or deductions from future Medicare reimbursements could create a nightmare. The laboratory testing order requirements pertain to both outside and in-house laboratories, such that a dermatologist who reads his/her own patient slides would have to maintain evidence that the slide readings were ordered and were medically necessary. [pagebreak]

A recent probe review of CPT code 88305 claims by the Medicare Administrative Contractor Cigna Government Services found a claims error rate of over 21 percent in Kentucky and over 56 percent in Ohio. That is huge! Consider the financial, physical, and emotional implications of a Medicare refund request based upon these percentages. The CGS review identified the following two deficiencies:

  • Lack of an order for the pathology testing
  • Documentation did not support CPT 88305 level of service

For dermatology, there are a few instances in which a CPT code other than 88305 may be used. They are:

CPT 88302 Skin, plastic repair

CPT 88304 Abscess, hematoma, salivary mucocele, skin tag, cyst, skin debridement, lipoma, thrombus, varicosity

CPT 88307 Soft tissue mass (except lipoma) biospy/simple excision (this code is rarely, if ever, appropriate in the dermatologic setting)

Maintenance of adequate test requisition records and precision in histopathology coding will protect you in the case of an audit.

Example 1: An outside laboratory processes your pathology specimens and sends you the slides for interpretation. You always send billing information to the lab along with the specimen. Medicare audits the lab and demands a refund for the technical component of processing billed to Medicare. Is Medicare correct in seeking a return of funds? [pagebreak]

Answer: Yes. According to Medicare regulations, evidence of a request for the testing must be documented. The billing information submitted to the lab is not sufficient evidence. The same billing information form containing a signed request for slide processing would suffice. Also adequate would be chart documentation specifying that the specimen was sent for histology processing.

Example 2: You excise an abscessed epidermoid cyst, evaluate the histopathology yourself, and bill CPT 88305 for your services, as the histopathology reveals both a cyst and an abscess.

Answer: Incorrect. Two CPT 88304-qualified entities do not make an 88305. Both cysts and abscesses are coded with CPT 88304. Although both are present on a histology specimen, the CPT code remains 88304.

Example 3: An excised suspected melanoma tissue specimen is serially cross-sectioned and processed into three tissue blocks. As the tissue presents a diagnostic challenge, slides from each of the three blocks are stained with a pan melanoma (MART-1 and tyrosinase) plus Ki-67 multiplex immunohistochemical stain. Since three antibodies are applied to slides generated from three blocks of tissue, a total of nine immunohistochemical stain applications are done. Consequently, three units of CPT 88342 and six units of CPT 88343 are billed.

Answer: Correct. For non-Medicare patients the above is the correct billing, producing a total of three 88342 and six 88343 charges. For Medicare patients, however, one must note that since there was only one tissue specimen and a multiplex (cocktail) stain was used on that specimen, there can only be one code charged one time, G0461.

Example 4: You biopsy a Medicare patient’s chart-documented atypical pigmented lesion, specify in the patient’s record that the specimen is being sent for histologic evaluation, and submit the tissue to an in-house dermatopathologist along with a signed requisition. You are confident that you have met appropriate Medicare requirements.

Answer: Correct. Both the need for a biopsy, suspected nevus atypia, and the need for histologic processing were documented in the patient record. The signed pathology requisition, although not technically required, will readily confirm the request for pathology services in the case of an audit.