Billing and Coding: Mohs Micrographic Surgery

This article gives guidance for billing, coding, and other guidelines in
relation to local coverage policy L34195 Mohs Micrographic Surgery.



**General Guidelines for Claims submitted to Part A or Part B MAC:**

Procedure codes may be subject to National Correct Coding Initiative (NCCI)
edits or OPPS packaging edits. Refer to NCCI and OPPS requirements prior to
billing Medicare. For services requiring a referring/ordering physician, the
name and NPI of the referring/ordering physician must be reported on the
claim. A claim submitted without a valid ICD-10-CM diagnosis code will be
returned to the provider as an incomplete claim under Section 1833(e) of the
Social Security Act. The diagnosis code(s) must best describe the patient's
condition for which the service was performed. For diagnostic tests, report
the result of the test if known; otherwise the symptoms prompting the
performance of the test should be reported.



**Advance Beneficiary Notice of Non-coverage (ABN) Modifier Guidelines**

An ABN may be used for services which are likely to be non-covered, whether
for medical necessity or for other reasons. Refer to CMS Publication 100-04,
Medicare Claims Processing Manual, Chapter 30, for complete instructions.

Effective from April 1, 2010, non-covered services should be billed with
modifier -GA, -GX, -GY, or -GZ, as appropriate.

The -GA modifier ("Waiver of Liability Statement Issued as Required by Payer
Policy") should be used when physicians, practitioners, or suppliers want to
indicate that they anticipate that Medicare will deny a specific service as
not reasonable and necessary and they do have an ABN signed by the beneficiary
on file. Modifier GA applies only when services will be denied under
reasonable and necessary provisions, sections 1862(a)(1), 1862(a)(9), 1879(e),
or 1879(g) of the Social Security Act. Effective April 1, 2010, Part A MAC
systems will automatically deny services billed with modifier GA. An ABN, Form
CMS-R-131, should be signed by the beneficiary to indicate that he/she accepts
responsibility for payment. The -GA modifier may also be used on assigned
claims when a patient refuses to sign the ABN and the latter is properly
witnessed. For claims submitted to the Part A MAC, occurrence code 32 and the
date of the ABN is required.



Modifier GX ("Notice of Liability Issued, Voluntary Under Payer Policy")
should be used when the beneficiary has signed an ABN, and a denial is
anticipated based on provisions other than medical necessity, such as
statutory exclusions of coverage or technical issues. An ABN is not required
for these denials, but if non-covered services are reported with modifier GX,
will automatically be denied services.



The -GZ modifier should be used when physicians, practitioners, or suppliers
want to indicate that they expect that Medicare will deny an item or service
as not reasonable and necessary and they have not had an ABN signed by the
beneficiary. If the service is statutorily non-covered, or without a benefit
category, submit the appropriate CPT/HCPCS code with the -GY modifier. An ABN
is not required for these denials, and the limitation of liability does not
apply for beneficiaries. Services with modifier GY will automatically deny.

**Documentation Requirements**

The patient's medical record should include but is not limited to:

  * The assessment of the patient by the ordering provider as it relates to the complaint of the patient for that visit,
  * Relevant medical history
  * Results of pertinent tests/procedures
  * Signed and dated office visit record/operative report (Please note that all services ordered or rendered to Medicare beneficiaries must be signed.)

For claims submitted to the Part A MAC: This coverage determination also
applies within states outside the primary geographic jurisdiction with
facilities that have nominated CGS Administrators, LLC to process their
claims.