Z20.01 vs Z86.1

Z20.01 (Contact with and (suspected) exposure to intestinal infectious diseases due to Escherichia coli (E. coli)) compared with Z86.1 (Personal history of infectious and parasitic diseases), from the official CMS tabular data.

Summary

These codes can be reported together when both conditions are documented, because Z20.01 lists Z86.1 under Excludes2, which marks them as distinct conditions.

Official rule

What is different?

The conditions named and billing status.Z20.01 is “Contact with and (suspected) exposure to intestinal infectious diseases due to Escherichia coli (E. coli)”; Z86.1 is “Personal history of infectious and parasitic diseases”. Z86.1 is a non-billable header; Z20.01 is billable.

Registry fact

Can these codes be reported together?

Yes, when both are documented.Z20.01 lists Z86.1 under Excludes2: “personal history of infectious and parasitic diseases (Z86.1-)”. Excludes2 marks distinct conditions that may both be reported when both are documented.

Official ruleGuide: Excludes1 vs Excludes2

Is there an Excludes1 relationship?

None.Neither entry carries an Excludes1 note that names the other code. Z20.01 carries 2 Excludes1 notes and Z86.1 carries 2 Excludes1 notes covering other codes; the side-by-side table quotes them.

Official rule

Is there an Excludes2 relationship?

Yes.Z20.01’s tabular entry: “personal history of infectious and parasitic diseases (Z86.1-)”. The note covers Z86.1.

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.Z86.1 is a non-billable header, but Z20.01 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?

Informational

Excludes2 relationship

Z20.01

Contact with and (suspected) exposure to intestinal infectious diseases due to Escherichia coli (E. coli)

↔

Z86.1

Personal history of infectious and parasitic diseases

What we found

Yes, when both are documented.Z20.01 carries an Excludes2 note covering Z86.1: “personal history of infectious and parasitic diseases (Z86.1-)”

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.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

	Z20.01Contact with and (suspected) exposure to intestinal infectious diseases due to Escherichia coli (E. coli)	Z86.1Personal history of infectious and parasitic diseases
Billing status	Billable	Non-billable header Report instead: Z86.11, Z86.12, Z86.13, Z86.14, Z86.15
Classification	Z00-Z99 — Factors Influencing Health Status and Contact with Health Services (Z00-Z99)	Z00-Z99 — Factors Influencing Health Status and Contact with Health Services (Z00-Z99)
Definition	Contact with and (suspected) exposure to intestinal infectious diseases due to Escherichia coli (E.	Personal history of infectious and parasitic diseases is a non-billable ICD-10-CM category code (Z86.1).
Includes	—	Conditions classifiable to A00-B89, B99
Excludes1	carrier of infectious disease (Z22.-) diagnosed current infectious or parasitic disease -see Alphabetic Index	personal history of infectious diseases specific to a body system sequelae of infectious and parasitic diseases (B90-B94)
Excludes2	personal history of infectious and parasitic diseases (Z86.1-)	—
Code first	—	any follow-up examination after treatment (Z09)
Code also	—	any follow-up examination (Z08-Z09)

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.

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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