I08 vs I34.1

I08 (Multiple valve diseases) compared with I34.1 (Nonrheumatic mitral (valve) prolapse), from the official CMS tabular data.

Summary

These codes should not be reported together because I34.1’s tabular entry lists I08 under Excludes1.

Official rule

What is different?

The conditions named and billing status.I08 is “Multiple valve diseases”; I34.1 is “Nonrheumatic mitral (valve) prolapse”. I08 is a non-billable header; I34.1 is billable.

Registry fact

Can these codes be reported together?

No.I34.1’s entry carries an Excludes1 note covering I08: “mitral valve disorder of unspecified cause with diseases of aortic and/or tricuspid valve(s) (I08.-)”. Both may be reported only when the documentation shows the two conditions are unrelated to each other (ICD-10-CM Official Guidelines, Section I.A.12.a).

Official ruleGuide: Excludes1 vs Excludes2

Is there an Excludes1 relationship?

Yes.I34.1’s tabular entry: “mitral valve disorder of unspecified cause with diseases of aortic and/or tricuspid valve(s) (I08.-)”. The note covers I08.

Official ruleGuide: Excludes1 vs Excludes2

Is there an Excludes2 relationship?

Yes.I08’s tabular entry: “multiple valve disease specified as nonrheumatic (I34.-, I35.-, I36.-, I37.-, I38.-, Q22.-, Q23.-, Q24.8-)”. The note covers I34.1.

Official ruleGuide: Excludes1 vs Excludes2

Is one more specific?

Not comparable.The codes sit in different categories; specificity is only comparable within one category.

Is one a parent or header code?

One is a header.I08 is a non-billable header, but I34.1 is not one of its subdivisions.

Registry fact

Are there sequencing instructions?

None.Neither entry carries a Code First or Use Additional Code note that names the other.

Official rule

Are there other coding relationships?

None found.No laterality, encounter-phase, Table of Neoplasms, Table of Drugs and Chemicals, or history-versus-active-disease relationship links these codes.

MedCoder-derived

Official rule: a tabular instructional note or a section of the ICD-10-CM Official Guidelines, quoted as published. Registry fact: the codes’ own published attributes (titles, billable status, position in the hierarchy, code set). MedCoder-derived: a reading MedCoder computes from those facts; it is not itself a rule. How to read the labels

Can these codes be reported together?

Excludes1 — generally not reported together

Excludes1 conflict

I34.1

Nonrheumatic mitral (valve) prolapse

↔

I08

Multiple valve diseases

What we found

No — do not report together.I34.1 carries an Excludes1 note covering I08: “mitral valve disorder of unspecified cause with diseases of aortic and/or tricuspid valve(s) (I08.-)”

Sole exception: when the two conditions are documented as unrelated to each other (ICD-10-CM Official Guidelines, Section I.A.12.a).

What to review

Report one of the two. Both may be reported only when the documentation shows the two conditions are unrelated to each other.

Guide: Excludes1 vs Excludes2 Check these on a claim

Why it matters

An Excludes1 note means the two conditions are not ordinarily reported together for the same encounter, because the classification treats them as mutually exclusive forms of the same condition. The documented exception is when the two conditions are unrelated to each other.

Source / rule

CMS ICD-10-CM tabular instructional notes; ICD-10-CM Official Guidelines, Section I.A.12.a

Informational

Excludes2 relationship

I08

Multiple valve diseases

↔

I34.1

Nonrheumatic mitral (valve) prolapse

What we found

Yes, when both are documented.I08 carries an Excludes2 note covering I34.1: “multiple valve disease specified as nonrheumatic (I34.-, I35.-, I36.-, I37.-, I38.-, Q22.-, Q23.-, Q24.8-)”

Excludes2 marks distinct conditions — both may be reported when both are documented.

What to review

Report both only when the documentation supports both conditions; otherwise report the one documented.

Guide: Excludes1 vs Excludes2 Check these on a claim

Why it matters

An Excludes2 note means the excluded condition is not part of the code above it, but a patient can have both. Report both when both are documented.

Source / rule

CMS ICD-10-CM tabular instructional notes

Official guidance behind these answers

Section I.A.12.a — Excludes1 · applies to: Excludes1
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. 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. For example, code F45.8, Other somatoform disorders, has an Excludes1 note for "sleep related teeth grinding (G47.63)," 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.
ICD-10-CM Official Guidelines FY2026
Section I.A.12.b — Excludes2 · applies to: Excludes2
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.
ICD-10-CM Official Guidelines FY2026

Quoted from the ICD-10-CM Official Guidelines for Coding and Reporting in effect for the release shown. The tabular notes above are the code-level instruction; these sections are the convention that says how such a note is applied. Source document (CMS PDF) · Release and checksum

Side by side

	I08Multiple valve diseases	I34.1Nonrheumatic mitral (valve) prolapse
Billing status	Non-billable header Report instead: I08.0, I08.1, I08.2, I08.3, I08.8	Billable
Classification	I00-I99 — Diseases of the Circulatory System (I00-I99)	I00-I99 — Diseases of the Circulatory System (I00-I99)
Definition	Multiple valve diseases is a non-billable ICD-10-CM category code (I08).	Nonrheumatic mitral (valve) prolapse is a billable ICD-10-CM diagnosis code (I34.1).
Includes	multiple valve diseases specified as rheumatic or unspecified	Floppy nonrheumatic mitral valve syndrome
Excludes1	endocarditis, valve unspecified (I38) rheumatic valve disease NOS (I09.1)	Marfan's syndrome (Q87.4-) mitral valve disease (I05.9) mitral valve failure (I05.8) mitral valve stenosis (I05.0) mitral valve disorder of unspecified cause with diseases of aortic and/or tricuspid valve(s) (I08.-) mitral valve disorder of unspecified cause with mitral stenosis or obstruction (I05.0) mitral valve disorder specified as congenital (Q23.2, Q23.9) mitral valve disorder specified as rheumatic (I05.-)
Excludes2	multiple valve disease specified as nonrheumatic (I34.-, I35.-, I36.-, I37.-, I38.-, Q22.-, Q23.-, Q24.8-)	—

Notes are the code’s own tabular entry, quoted as published. A note that names the other code is the one the verdict above rests on.

The distinction

I08 is the rheumatic-or-unspecified side of valve disease when more than one valve is involved; I34.1 is one specific nonrheumatic condition of one valve — mitral prolapse. Which side a record lands on is decided by two documented facts, the cause and the number of valves, and the two categories describe each other with different Excludes note types, which is why Claim Check flags this pair under both.

The deciding question

Is the valve disease documented as nonrheumatic, and is more than one valve involved?

Read the cause first. If the record says nonrheumatic, the I34–I37 categories apply, one code per valve — I34.1 for mitral prolapse — and I08 does not, because I08’s Excludes2 sends “multiple valve disease specified as nonrheumatic” to those categories. If the cause is rheumatic or not stated, the I05–I08 side applies: I34’s Excludes1 lists “mitral valve disease (I05.9)” and “mitral valve disorder of unspecified cause with diseases of aortic and/or tricuspid valve(s) (I08.-)”, so an unstated cause defaults to the rheumatic categories, and a second valve moves the code from I05.- to I08.-. Then count valves: I08 includes only multiple-valve disease; a single mitral disorder of rheumatic or unspecified cause is I05.-, not I08.

Worked examples

Landing on I08.0

The record documents rheumatic disease of both the mitral and aortic valves, with no mention of prolapse or of a separate nonrheumatic condition.

I08.0 — Rheumatic disorders of both mitral and aortic valves (sole valve code)

I34.1 is not added: I34’s Excludes1 sends a mitral disorder specified as rheumatic to I05.- and one with aortic involvement to I08.-, and I08.0’s own inclusion term covers involvement “specified as rheumatic or unspecified.”

Landing on I34.1

Echocardiography documents nonrheumatic mitral valve prolapse; no other valve is involved and no rheumatic history is recorded.

I34.1 — Nonrheumatic mitral (valve) prolapse (sole valve code)

If a second valve were also documented as nonrheumatic — nonrheumatic aortic stenosis, say — the answer is still not I08: its Excludes2 points nonrheumatic multiple-valve disease to the individual categories, so I34.1 and I35.0 would each be reported.

Why coders confuse them

The two categories point at each other with different note types. At I08 the note toward the nonrheumatic codes is an Excludes2 — nonrheumatic multiple-valve disease is simply not what I08 covers. At I34 the note toward I08.- is an Excludes1 — a mitral disorder of unspecified cause that also involves another valve belongs in I08, and cannot also be an I34 code. Claim Check reports whichever note it reads at each code, so the pair surfaces under both, and the stricter one governs. The Excludes1-vs-Excludes2 guide walks this exact pair.

The defaults run the opposite way from most coders’ instinct. “Mitral valve disease” with no cause documented is not I34.-; I34’s Excludes1 sends it to I05.9, the rheumatic-unspecified code. The nonrheumatic categories require the record to say nonrheumatic. And the sibling categories are not even consistent with each other: I35, the nonrheumatic aortic category, uses an Excludes2 toward I08.- where I34 uses an Excludes1 — so the same logic reads differently one valve over, and only reading the note at the code in hand settles it.

FAQ

Can I08 and I34.1 be reported on the same claim?

Not for the same valve disease. From I34’s side the relationship is an Excludes1, so a mitral disorder that belongs in I08 cannot also be coded as I34.1. Both would be reported only if the record clearly documents two distinct conditions — the Guidelines’ Excludes1 exception for unrelated conditions — and when that is not clear, the Guidelines say to query the provider.

Where does “mitral valve disease” go when no cause is documented?

To the rheumatic categories. I34, Nonrheumatic mitral valve disorders, carries an Excludes1 for “mitral valve disease (I05.9)”, so an unstated cause defaults to I05.9, Rheumatic mitral valve disease, unspecified; with a second valve involved it becomes an I08.- code. The nonrheumatic codes require the record to say nonrheumatic.

How is nonrheumatic disease of two valves coded?

With one code per valve from the nonrheumatic categories — for example I34.1 with I35.0 — not with I08. I08’s Excludes2 lists “multiple valve disease specified as nonrheumatic (I34.-, I35.-, I36.-, I37.-, I38.-, Q22.-, Q23.-, Q24.8-)”; I08 covers only multiple-valve disease specified as rheumatic or unspecified.

Excludes1 vs Excludes2: when two codes can be reported together·I08.0 — Rheumatic disorders of both mitral and aortic valves·I05.9 — Rheumatic mitral valve disease, unspecified

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Derived from the official CMS ICD-10-CM tabular data (FY2027). A coding-rule comparison, not billing advice: payer-specific edits and medical-necessity policy are outside its scope. All data sources