United Health to Denial Claims Based on ICD-10

UnitedHealthcare (UHC) Medicare Advantage will begin reinforcing denials
based on its interpretation of the International Classification of Disease, 10 th
Edition, Clinical Modification (ICD-10-CM) Excludes 1.
(https://www.uhcprovider.com/content/dam/provider/docs/public/policies/me
dadv-reimbursement/rpub/UHC-MEDADV-RPUB-JAN-2026.pdf)

As announced by UHC, the anticipated action is related to its guidelines for
inpatient claim types. The UCH policy is effective Feb. 1 as part of its
comprehensive diagnosis code requirement policy for both professional
and facility services previously announced in 2024.

Since HIPAA requires that all covered entities (which providers, health
plans, and a healthcare clearinghouse) to comply with ICD-10-CM
conventions (Index and Table) and Guidelines whose official interpretations
by the American Hospital Association’s Central Office are published in the
AHA Coding Clinic for ICD-10-CM and ICD-10-PCS, facilities, physicians,
coders, and clinical documentation integrity (CDI) must effectively
negotiated with UHC and other payers how ICD-10-CM truly governs the
Excludes1 rules and confront payer denial errors when indicated.

UHC states in its 2024 policy cited above that an ICD-10-CM Exclude1
diagnosis means “‘NOT CODED HERE!’ An Excludes1 note indicates that
the code excluded should never be used at the same time as the code
above the Excludes1 note” and “providers should refer to the official ICD-
10-CM Guidelines for appropriate Excludes1 diagnoses”.

First, let’s remind UHC that providers should refer to the ICD-10-CM
Tabular List of Diseases and Injuries for a list of Excludes1 diagnoses, not
the ICD-10-CM Guidelines since they don’t exist there.  Access the new
April 2026 version of the Table at https://www.cms.gov/files/zip/april-1-
2026-code-tables-tabular-index.zip. 

Second, let’s remind UHC and other payers that while the fiscal year (FY)
2026 ICD-10-CM Official Guidelines for Coding and Reporting, available at
https://www.cms.gov/files/document/fy-2026-icd-10-cm-coding-
guidelines.pdf, do state, “A type 1 Excludes note is a pure excludes note. It
means “NOT CODED HERE!”

An Excludes1 note indicates that the excluded code should never be used
at the same time as the code above the Excludes1 note. An Excludes1 is
used when two conditions cannot occur together, such as a congenital form
versus an acquired form of the same condition,” these same guidelines
also state, “an exception to the Excludes1 definition is the circumstance
when the two conditions are unrelated to each other.” 

Consequently, UHC cannot simply deny all circumstances whereby both an
Excludes1 code and the code above it are reported at the same time since
these two codes may not be clinically related to each other. 

For example, the Guidelines explicitly cite ICD-10-CM codes F45.8 and
G47.63 as potentially unrelated to each other when listed in the ICD-10-CM
as follows:

F45.8 Other somatoform disorders
Psychogenic dysmenorrhea
Psychogenic dysphagia, including ‘globus hystericus’
Psychogenic pruritus
Psychogenic torticollis
Somatoform autonomic dysfunction
Teeth grinding

Excludes1: sleep related teeth grinding (G47.63)

These guidelines explicitly state, “Only one of these two codes should be
assigned for teeth grinding. However psychogenic dysmenorrhea is also an
inclusion term under F45.8, and a patient could have both this condition and
sleep related teeth grinding. In this case, the two conditions are clearly
unrelated to each other, and so it would be appropriate to report F45.8 and
G47.63 together.”

It appears that these Guidelines allow the coder to judge whether two
codes are related to each other; however, when in doubt, they explicitly
state, “If it is not clear whether the two conditions involving an Excludes1
note are related or not, query the provider.”

The AHA Coding Clinic for ICD-10-CM cites other examples of Excludes1
diagnoses that are unrelated to each other, that would challenge UHC’s
denials, such as:

– D64.81, Anemia due to antineoplastic chemotherapy and C92.-,
Myeloid leukemia.  While category D64, Other Anemia, has an
Exclude1 note for C92.- codes, which means the two codes cannot
be assigned together, these are separate conditions, which are
unrelated, as the anemia was caused by the chemotherapy not the
AML and thus an exception to the Excludes1 note so that both codes
can be reported.  (Coding Clinic, 3 rd Quarter, 2021, page 4).

– I63.231, Cerebral infarction due to unspecified occlusion or
stenosis of right carotid artery and I65.22, Occlusion and
stenosis of left carotid artery.  While category I65, Occlusion and
stenosis of precerebral arteries, not resulting in cerebral infarction,
has an Excludes1 note for all I63.0-I63.2 codes, since the stenosis of
the left carotid artery was unrelated to the cerebral infraction involved
with the right carotid artery, both can be reported (Coding Clinic, 3 rd
Quarter, 2020, pages 28-29)

– Many others – Use key words “Excludes1” and “unrelated” when
searching Coding Clinic Advisor or other Coding Clinic resources to
find other examples.

One’s own research of the ICD-10-CM can identify other reasonably
defendable unrelated circumstances affecting by the Excludes1
convention. These include:

– A nonruptured cerebral berry aneurysm (I67.1) that is in a different
location from one that did rupture (I60.7, Nontraumatic
subarachnoid hemorrhage from unspecified intracranial artery).
Reference the Coding Clinic, 3rd Quarter, 2021, page 4 cited above.

– Non-ischemic myocardial injury (I5A) due to postmyocardial infarction
(MI) related pericarditis (I24.1, Dressler’s syndrome) occurring within
28 days of an acute myocardial infarction. The troponin elevation
from Dressler’s syndrome is arguably unrelated to the patient’s recent
acute myocardial infarction.

– Primary pulmonary hypertension (I27.0) that coexists with essential
hypertension (I10) and its consequences (hypertensive left heart
disease (I11.x) or hypertensive chronic kidney disease (I12.x) or any
I10-I1A code. These are obviously different since primary pulmonary
hypertension involves the pulmonary artery while systemic
hypertension involves every other artery; however, if UHC strictly
denies one or the other code based on the Excludes1 convention,
facilities and physicians will significantly lose reimbursement and
quality-related risk adjustments.

– I’m sure you can find others.

Consequently, it is PERFECTLY LEGAL for two “Excludes1” codes to
coexist if these are clinically unrelated to each other, something UHC must
address before removing the code.  CDIs and coders, however, may need
to ask physicians to explicitly document that the two conditions are
unrelated as to survive UHC’s denials, given the Guidelines requirements
to query if it is not clear that these two conditions are indeed unrelated.

Another challenge involves which Excludes1 code should be removed
when related to each other, the one with the Excludes1 note or the one
above it.

As the Guidelines are not overt, Coding Clinic, 4 th Quarter, 2018, pp. 87-88
states that the code listed next to the Excludes1 note is preferred over the
code above it. Caveats include the following:

1. Sometimes there are bidirectional Excludes1 notes between two
   codes; the coder or CDI must decide which one best describes the
   patient’s circumstances.
2. The associated code above the Excludes1 note may better describe
   the patient’s condition (Coding Clinic, 2nd Quarter, 2019, pages 7-8),
   is more acute (Coding Clinic, 3rd Quarter, 2019, p. 17; 2nd Quarter, 2019, p. 26),
   or serves as the underlying cause of a symptom code
   listed with the Excludes1 note (Coding Clinic, 3rd Quarter, 2021, pp
   3-4), justifying its use over the code next to the Excludes1 instruction.

Facilities and physician practices would be wise to address these through
their internal coding policies or their engagement with payers so that UHC’s
and other’s denials may be mitigated.

There is some good news in that it appears that the CDC’s ICD-10-CM
Coordination and Maintenance Committee is converting many Excludes1
notes to Excludes2 notes, represented in the Guidelines as  “Not included
here” which indicates that the condition excluded is not part of the condition
represented by the code, but a patient may have both conditions at the
same time.

The ICD-10-CM guidelines explicitly state that when an Excludes2 note
appears under a code, it is acceptable to use both the code and the
excluded code together, when appropriate. 

There are many others for which research and coder/CDI engagement and
education are encouraged.

As a final note, when there are conflicting Excludes1 and Excludes2 notes
in the ICD-10-CM Table, the Excludes2 note prevails as discussed in
Coding Clinic, 4 th Quarter, 2017, pages 108-109.  Consider incorporating
this official advice in a coding policy or compliance program.

In summary, it appears that the UHC published Excludes1 policies are
incomplete and require clarification. Facilities and physicians must address
these upcoming denials through revisions to their coding policies, engage
CDI teams to anticipate Excludes1 denials as to ascertain whether two
affected conditions are related or not, and develop documentation
infrastructure that helps avoid these denials in the first place.

Technology companies like Solventum, TruBridge, or Optum could assist as
to alert CDI and coding specialists of potential denials based on the
Excludes1 convention and assist in determining when applicable codes are
related or not.