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I70.632 vs I70.639

I70.632 (Atherosclerosis of nonbiological bypass graft(s) of the right leg with ulceration of calf) compared with I70.639 (Atherosclerosis of nonbiological bypass graft(s) of the right leg with ulceration of unspecified site), from the official CMS tabular data.

Current data releases:ICD-10-CM FY2027 · ICD-10-PCS FY2027 · HCPCS October 2026 · MS-DRG v44 · Medicare Code Editor v44.0 · NCCI PTP Q4 2026 · MUE Q4 2026 · NCD code lists 2026-01 · LCD export September 28, 2026 · All releases and sources

Summary

These codes represent different levels of specificity within category I70: I70.632 is the more specific code and I70.639 is the unspecified one.

MedCoder-derived
What is different?

Title wording.The titles share “Atherosclerosis of nonbiological bypass graft(s) of the right leg with ulceration of”; I70.632 says “calf” where I70.639 says “unspecified site”.

Registry fact

Can these codes be reported together?

Not ordinarily.I70.632 is the more specific code and I70.639 is the unspecified one, in the same category. When the documentation supports the more specific code, the unspecified code is not added for the same condition (ICD-10-CM Official Guidelines, Section I.B.18).

MedCoder-derivedGuide: Other vs unspecified (NEC vs NOS)

Is there an Excludes1 relationship?

None.Neither entry carries an Excludes1 note that names the other code.

Official rule

Is there an Excludes2 relationship?

None.Neither entry carries an Excludes2 note that names the other code. I70.632 carries 8 Excludes2 notes and I70.639 carries 8 Excludes2 notes covering other codes; the side-by-side table quotes them.

Official rule

Is one more specific?

Yes.I70.632’s title names the condition; I70.639’s title is the unspecified form (“Atherosclerosis of nonbiological bypass graft(s) of the right leg with ulceration of unspecified site”).

MedCoder-derivedGuide: Other vs unspecified (NEC vs NOS)

Is one a parent or header code?

No.Both are billable codes, and neither contains the other.

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?

Review

Specificity relationship

I70.639
Atherosclerosis of nonbiological bypass graft(s) of the right leg with ulceration of unspecified site
↔
I70.632
Atherosclerosis of nonbiological bypass graft(s) of the right leg with ulceration of calf

What we found

Not ordinarily reported together for the same condition. No Excludes1/Excludes2 relationship is listed between I70.639 and I70.632, but they describe overlapping diagnoses in the same category (Both are children of the same I70 category.).

When documentation supports the more specific code, the unspecified code should generally not be added for the same condition (ICD-10-CM Official Guidelines, Section I.B.18).

What to review

When the documentation supports the more specific code, report it and leave the unspecified code off for the same condition.

Guide: Other vs unspecified (NEC vs NOS)Check these on a claim

Why it matters

No Excludes note links these codes, but they describe overlapping diagnoses and one of them is unspecified. When documentation supports the more specific code, the unspecified code should generally not be added for the same condition.

Source / rule

ICD-10-CM Official Guidelines, Section I.B.18

Official guidance behind these answers

  • Section I.B.18 — Use of Sign/Symptom/Unspecified Codes · applies to: Unspecified codes

    Sign/symptom and “unspecified” codes have acceptable, even necessary, uses. While specific diagnosis codes should be reported when they are supported by the available medical record documentation and clinical knowledge of the patient’s health condition, there are instances when signs/symptoms or unspecified codes are the best choices for accurately reflecting the healthcare encounter. Each healthcare encounter should be coded to the level of certainty known for that encounter. As stated in the introductory section of these official coding guidelines, a joint effort between the healthcare provider and the coder is essential to achieve complete and accurate documentation, code assignment, and reporting of diagnoses and procedures. The importance of consistent, complete documentation in the medical record cannot be overemphasized. Without such documentation accurate coding cannot be achieved. The entire record should be reviewed to determine the specific reason for the encounter and the conditions treated. If a definitive diagnosis has not been established by the end of the encounter, it is appropriate to report codes for sign(s) and/or symptom(s) in lieu of a definitive diagnosis. When sufficient clinical information isn’t known or available about a particular health condition to assign a more specific code, it is acceptable to report the appropriate “unspecified” code (e.g., a diagnosis of pneumonia has been determined, but not the specific type). […]

    ICD-10-CM Official Guidelines FY2027

  • Section I.B.2 — Level of Detail in Coding · applies to: Level of detail

    Diagnosis codes are to be used and reported at their highest number of characters available and to the highest level of specificity documented in the medical record. ICD-10-CM diagnosis codes are composed of codes with 3, 4, 5, 6 or 7 characters. Codes with three characters are included in ICD-10-CM as the heading of a category of codes that may be further subdivided by the use of fourth and/or fifth characters and/or sixth characters, which provide greater detail. A three-character code is to be used only if it is not further subdivided. A code is invalid if it has not been coded to the full number of characters required for that code, including the 7th character, if applicable.

    ICD-10-CM Official Guidelines FY2027

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

Similar descriptions do not make codes interchangeable. The documentation and the official instructions decide which code applies.

Official descriptionDiffers
I70.632

Atherosclerosis of nonbiological bypass graft(s) of the right leg with ulceration of calf

I70.639

Atherosclerosis of nonbiological bypass graft(s) of the right leg with ulceration of unspecified site

StatusSame for both
Billable
Excludes2Same for both
  • arteriosclerotic cardiovascular disease (I25.1-)
  • arteriosclerotic heart disease (I25.1-)
  • atheroembolism (I75.-)
  • cerebral atherosclerosis (I67.2)
  • coronary atherosclerosis (I25.1-)
  • mesenteric atherosclerosis (K55.1)
  • precerebral atherosclerosis (I67.2)
  • primary pulmonary atherosclerosis (I27.0)
Use additional codeSame for both
  • code to identify severity of ulcer (L97.-)
  • code, if applicable, to identify chronic total occlusion of artery of extremity (I70.92)
  • code to identify:
CategorySame for both

I70 Atherosclerosis

ChapterSame for both

I00-I99 — Diseases of the Circulatory System (I00-I99)

IncludesSame for both
  • any condition classifiable to I70.611 and I70.621
  • chronic limb-threatening ischemia of nonbiological bypass graft(s) of the right leg with ulceration
  • critical limb ischemia of nonbiological bypass graft(s) of the right leg with ulceration
  • arteriolosclerosis

No Excludes1, Code first, Code also and 7th character note at either code.

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. In a row that differs, notes every code shares are dimmed.

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