There is almost zero room for opinion in coding. Almost every coding question has one correct answer from an appropriate source. Coding direction should not be based on “I heard” or “They said” or anyone’s opinion. Answers to coding and coverage questions should include a reference indicating the official source for the answer.
Diagnosis Codes
The official listing of current ICD-10-CM codes in the United States is free and online. It can be found here: https://www.cms.gov/medicare/coding-billing/icd-10-codes. Many practitioners commit errors in their diagnosis coding when doing online searches and / or relying on third party listings of ICD-10-CM codes. One reason for this is the ICD-10-CM code set resets once a year every year. Every year there are additions, deletions, and changes to the code set. Online searches often produce results that are incorrect because changes have occurred since the information found in the result was posted.
Another common error that results from performing online searches for diagnosis codes is findings and using “unspecified” ICD10-CM codes. Use of an “unspecified” ICD10-CM code normally indicates that the documentation did not contain the information needed to select the appropriately specific code.
For example, the ICD10-CM code options for hallux valgus (acquired) include:
| ICD10-CM Code | Description |
| M20.10 | Hallux valgus (acquired), unspecified foot |
| M20.11 | Hallux valgus (acquired), right foot |
| M20.12 | Hallux valgus (acquired), left foot |
When considering these options, a selection of M20.10 would indicate that the documentation did not specify whether the pathology involved the right foot or left foot. In this case, the use of an “unspecified” ICD10-CM code would indicate to a third party payer that the documentation was incomplete and did not “specify” what it should have in order to select a more specific diagnosis code. Using this example, if the documentation did, in fact, specify whether the right or left foot was involved, it would be inappropriate to choose an ICD10-CM code which indicated that right versus left designation was left “unspecified” in the documentation.
Another example can be found in the ICD10-CM coding for a diabetic foot ulcer. Among other required ICD10-CM codes, the L97- ICD10-CM code options for a left plantar heel diabetic foot ulcer whose deepest depth of tissue exposed is subcutaneous tissue include:
| L97 - ICD10-CM | Description |
| L97.421 | Non-pressure chronic ulcer of left heel and midfoot limited to breakdown of skin |
| L97.422 | Non-pressure chronic ulcer of left heel and midfoot with fat layer exposed |
| L97.423 | Non-pressure chronic ulcer of left heel and midfoot with necrosis of muscle |
| L97.424 | Non-pressure chronic ulcer of left heel and midfoot with necrosis of bone |
| L97.425 | Non-pressure chronic ulcer of left heel and midfoot with muscle involvement without evidence of necrosis |
| L97.426 | Non-pressure chronic ulcer of left heel and midfoot with bone involvement without evidence of necrosis |
| L97.428 | Non-pressure chronic ulcer of left heel and midfoot with other specified severity |
| L97.429 | Non-pressure chronic ulcer of left heel and midfoot with unspecified severity |
If the documentation of this ulcer were thoroughly and properly performed, it would include the fact that the deepest depth of tissue exposed is subcutaneous tissue. A selection of L97.429 would indicate that the documentation was incomplete and did not specify the severity of the ulcer. The more appropriate selection in this example is L97.422, reflecting the thorough documentation that did, in fact, specify the depth of the ulcer.
Incorrect ICD10-CM coding can be problematic in the case of an audit performed by a third-party payer or its representative. If the documentation specified what it should, but the ICD10-CM code selected indicates this specification was not present, a case for incorrect coding could be made.
Medicare Coverage Guidelines
Medicare is a national program, but it is administered on a local level by Medicare Administrative Contractors (MACs). There are seven Part B MACs in the United States. Part B services are practitioner services like ulcer debridement, evaluation & management services, and application of multilayer compression. Some of the Part B MAC’s have large jurisdictions, including 13 states and some have small jurisdictions, including only two states. The identity of the seven Part B MACs and their jurisdictions are:
First Coast Service Options:
• Florida
• Puerto Rico
• Virgin Islands
Palmetto GBA:
• Alabama
• Georgia
• Tennessee
• South Carolina
• Virginia
• West Virginia
• North Carolina
Novitas Solutions, Inc:
• Colorado
• New Mexico
• Oklahoma
• Texas
• Arkansas
• Louisiana
• Mississippi
• Delaware
• Washington DC
• Maryland
• New Jersey
• Pennsylvania
Wellpoint Federal:
• Illinois
• Minnesota
• Wisconsin
• Connecticut
• New York
• Maine
• Massachusetts
• New Hampshire
• Rhode Island
• Vermont
CGS Administrators, LLC
• Kentucky
• Ohio
WPS Ins Corp
• Iowa
• Kansas
• Missouri
• Nebraska
• Indiana
• Michigan
Noridian Healthcare Solutions, LLC
• Alaska
• Idaho
• Oregon
• Washington
• Arizona
• Montana
• North Dakota
• South Dakota
• Utah
• Wyoming
• California
• Hawaii
• Nevada
Most of the time, when providing Part B services to Medicare beneficiaries, guidance regarding coding, coverage, medical necessity, and documentation requirements comes from the Part B MAC, not from Medicare. Most of the time, the question of, “What are the Medicare guidelines for ________” is the incorrect question and instead that question should be, “What are my Part B MAC’s guidelines for ________?” Most of the time, the question of, “How frequently does Medicare allow payment for ________” is the incorrect question and instead that question should be, “How frequently does my Part B MAC allow payment for ________?” Most of the time, the question of, “Does Medicare cover ________” is the incorrect question and instead that question should be, “Does my Part B MAC cover ________?”
Providers and their staff must know which Part B MAC has jurisdiction over their state / territory. When navigating to their Part B MAC’s website, providers can find a list of coverage policies. Here, a listing of the Part B MAC’s Local Coverage Determinations (LCDs) can be found. LCDs normally provide guidance regarding coverage, medical necessity, limitations, documentation requirements, and more. In many cases an LCD is accompanied by a LCD Reference Article that offers guidance regarding coding. Part B MACs choose to issue LCDs for certain services. An important point that is often misunderstood is that different Part B MACs issue LCDs for different services. For example, one Part B MAC may have an LCD for ulcer debridement while another may not. Perhaps even more important to understand is that two different Part B MAC’s LCDs may have different guidance. This is why it is so important for providers to look for guidance from their own Part B MAC rather than from national forums in many cases. Furthermore, providers in one Part B MAC’s jurisdiction may not find the correct guidance if speaking to a colleague about coverage guidelines if that colleague practices in a state that falls under the jurisdiction of a different Part B MAC. A provider in Texas may be subject to different guidelines than a provider in New York State for certain services.
It is good practice for providers to review the list of LCDs issued by their Part B MAC. Here is where providers can find those listings:
Noridian Part B MAC – https://www.cms.gov/medicare-coverage-database/reports/local-coverage-final-lcds-contractor-report.aspx?contractorName=5&contractorNumber=360%7c1&lcdStatus=all
Novitas Part B MAC – https://www.cms.gov/medicare-coverage-database/reports/local-coverage-final-lcds-contractor-report.aspx?contractorName=6&contractorNumber=331%7c1&lcdStatus=all
Wellpoint Federal Part B MAC – https://www.cms.gov/medicare-coverage-database/reports/local-coverage-final-lcds-contractor-report.aspx?contractorName=36&contractorNumber=507%7C1&lcdStatus=all&sortBy=title
Palmetto Part B MAC – https://www.cms.gov/medicare-coverage-database/reports/local-coverage-final-lcds-contractor-report.aspx?contractorName=2&contractorNumber=all&lcdStatus=all
First Coast Services Part B MAC – https://www.cms.gov/medicare-coverage-database/reports/local-coverage-final-lcds-contractor-report.aspx?contractorName=4&contractorNumber=368%7c1&lcdStatus=all
Furthermore, it is recommended that providers and/or their staff subscribe to the e-mail listserv of the Part B MAC who has jurisdiction over their state / territory. Updates to these coverage determinations are shared via these listservs.
Durable Medical Equipment
While Part B MACs typically govern coverage of practitioner services performed for Medicare Part B beneficiaries, DME MACs typically govern coverage of durable medical equipment, like surgical dressings. Just as the Part B MACs issue LCD’s, the DME MACs do the same. There are only two DMEMACs in the United States, CGS DME MAC and Noridian DME MAC. It is recommended that providers who prescribe and / or supply DME review the list of LCDs issued by their DME MAC. Here is where providers can find those listings:
Noridian DME MAC – https://www.cms.gov/medicare-coverage-database/reports/local-coverage-final-lcds-contractor-report.aspx?contractorName=5&contractorNumber=389%7c1&lcdStatus=all
Both of these DME MACs have a Surgical Dressings LCD and Surgical Dressings Policy Article that outline their coverage guidelines for items like collagen, foam, hydrogel, compression garments, and other surgical dressings.
It is also recommended that providers and/or their staff who are involved with prescribing and / or supplying DME subscribe to the e-mail listserv of the DME MAC which has jurisdiction over their state. Updates to these coverage determinations are shared via these listservs.
Non-Medicare Payers
Non-Medicare third party payers also issue coverage determinations. These are often found on the website of the third party payer. In some cases, third party payers do not issue coverage determinations and instead default to the coverage guidelines of the policies of the Part B MAC who has jurisdiction in the state where the services were provided. It is best that providers check with each third party to whom they submit claims to see what coverage policies each of their third party payers has issued. Sometimes, the coverage guidelines for the same service or product may differ from one patient to the next even within the same practice in the same state if different third party payers have different coverage guidelines for the same service in that state.
No Coverage Policy
Sometimes a situation arises where a third-party payer does not have a coverage policy for a certain service. For example, none of the Part B MACs have an LCD for the service of a bunionectomy. In the absence of a coverage policy, most third-party payers, including the Part B MACs, state coverage and frequency considerations are based on medical necessity. This includes the presence and documentation of the medical necessity of the service performed and / or the product dispensed.
Summary
Unless providers are outsourcing this type of work, they need to know where to find correct coding guidance and the coverage guidelines of the third party payers to whom they are submitting claims. When it comes to Medicare beneficiaries, this means knowing who the provider’s Part B MAC and DME MAC are. For non-Medicare payers, this may require reviewing a number of policies, depending on how many third party payers the provider submits claims to. Providers can stay current with these policies by subscribing to the listserv of the third party payer.
Author: Jeffrey D. Lehrman, DPM, FASPS, MAPWCA, CPC, CPMA, CEMC
Co-Authors: Joshua Trujillo, Katelyn Norkowski
