Excludes1 vs Excludes2: When Two ICD-10-CM Codes Can Be Reported Together

Both note types are defined in one place: Section I.A.12 of the Official Guidelines. The preamble is worth reading before either definition, because it names the one thing the two types share:

Official source

“The ICD-10-CM has two types of excludes notes. Each type of note has a different definition for use, but they are all similar in that they indicate that codes excluded from each other are independent of each other.”

Excludes1 (Section I.A.12.a)

Official source

“A type 1 Excludes note is a pure excludes note. It 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. An Excludes1 is used when two conditions cannot occur together, such as a congenital form versus an acquired form of the same condition.”

Excludes2 (Section I.A.12.b)

Official source

“A type 2 Excludes note represents ‘Not included here.’ An excludes2 note 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. When an Excludes2 note appears under a code, it is acceptable to use both the code and the excluded code together, when appropriate.”

The difference is not degree of severity. Excludes1 is a statement about the conditions — they are mutually exclusive, so two codes for them would be a contradiction. Excludes2 is a statement about the code’s scope — the other condition lives somewhere else in the classification, and if the patient has it, code it there.

The FY 2027 tabular carries roughly 2,600 Excludes1 note blocks and 1,200 Excludes2 blocks, and a single category can carry both. I10 is the everyday example: its Excludes1 sends hypertension complicating pregnancy to the O-codes (a different condition, coded elsewhere entirely), while its Excludes2 for hypertension involving vessels of the brain (I60–I69) or eye (H35.0-) simply says those are separate conditions a hypertensive patient may also have.

Excludes1 has one carve-out, stated in the same section, and it is the part most often missed:

Official source

“An exception to the Excludes1 definition is the circumstance when the two conditions are unrelated to each other. If it is not clear whether the two conditions involving an Excludes1 note are related or not, query the provider.”

The Guidelines illustrate it with F45.8, Other somatoform disorders, which carries an Excludes1 note for sleep related teeth grinding (G47.63):

Official source

“…because ‘teeth grinding’ is an inclusion term under F45.8. 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.”

Read what the exception actually turns on. F45.8 is a residual code covering several unrelated inclusion terms. When the reason for F45.8 is the same condition the Excludes1 names (teeth grinding), the note holds absolutely — pick one. When the reason for F45.8 is a different inclusion term (psychogenic dysmenorrhea), the two codes describe two different conditions, the Excludes1 no longer describes the situation, and both are reported. The exception is not “Excludes1 is advisory.” It is “an Excludes1 only forbids the pairing it is actually about.”

The tabular makes the note reciprocal — G47.63 carries its own Excludes1 for psychogenic bruxism (F45.8) — so the same reasoning applies from either code.

Among the pairs Claim Check users bring most often is I08, Multiple valve diseases, with I34.1, Nonrheumatic mitral (valve) prolapse — and it gets flagged under both note types. That is not a tool error. The two categories point at each other with different notes:

• At I08, the note toward the nonrheumatic codes is an Excludes2: “multiple valve disease specified as nonrheumatic (I34.-, I35.-, I36.-, I37.-, I38.-, Q22.-, Q23.-, Q24.8-)”. Nonrheumatic multi-valve disease is simply not what I08 covers.
• At I34, the note toward I08 is an Excludes1: “mitral valve disorder of unspecified cause with diseases of aortic and/or tricuspid valve(s) (I08.-)”. A mitral disorder of unspecified cause that also involves another valve belongs in I08, not I34 — the same patient’s valve problem cannot be both.

So the question the pair actually asks is: which valve disease does this patient have? I08 includes “multiple valve diseases specified as rheumatic or unspecified.” If the mitral prolapse is documented as nonrheumatic and it is the only valve involved, I34.1 stands alone and I08 does not apply. If several valves are involved and the cause is rheumatic or unspecified, I08 applies and I34.1 does not — I34’s Excludes1 says so directly. Reporting both means the record has been read as saying two contradictory things about the same valves, and that is a documentation question, not a sequencing one.

The lesson generalises: Excludes notes are written at a code and read from it. Two codes can describe their relationship differently from each end, and the stricter note governs the pairing.

In the demand data behind this site, more than half of all note-based conflicts users check are Excludes2 — which, by the Guidelines’ own definition, are pairings that may be correct. An Excludes2 flag is worth a glance to confirm the patient genuinely has both conditions; it is not a defect to be cleared by deleting a code. An Excludes1 flag is the one that needs a decision: same condition (drop one), unrelated conditions (keep both), or unclear (query).

This is a classification convention, not a payer rule. Whether a particular payer’s edit engine rejects, warns on, or ignores an Excludes1 pairing is that payer’s policy — the Guidelines govern what is correct, and the answer above does not change with the payer.

1. Read the note at each code of the pair, in the Tabular — the two codes can describe their relationship differently (the I08 / I34 example).
2. If either note is Excludes1, ask whether both codes describe the same condition (one is an inclusion term of the other, or congenital versus acquired). Same condition → one code only.
3. If the documented conditions are clearly different (the F45.8 pattern), both may be reported — Section I.A.12.a’s exception.
4. If it is not clear whether they are related, query the provider; do not resolve it by dropping a code.
5. If the note is Excludes2, report both when the patient has both; the note is information, not a prohibition.

• Deleting a code to clear an Excludes2 flag — Excludes2 permits the pair.
• Reading Excludes1 as absolute — the unrelated-conditions exception exists and is in the Guidelines’ own example.
• Reading the note at only one code of the pair when the two disagree by direction.
• Resolving an unclear Excludes1 without a query.

• Whether the two documented conditions are the same condition described twice, or two distinct conditions — the fork between “one code” and “both codes” under an Excludes1.
• The provider’s statement, when the record is ambiguous; the Guidelines direct a query.
• Which condition is actually present, for a pair that is Excludes1 from one side and Excludes2 from the other.