A27 (Leptospirosis)
compared with
A66.9 (Yaws, unspecified),
from the official CMS tabular data.
Summary
These codes can be reported together when both conditions are documented, because A66.9 lists A27 under Excludes2, which marks them as distinct conditions.
Official rule
What is different?
The conditions named and billing status.A27 is “Leptospirosis”; A66.9 is “Yaws, unspecified”. A27 is a non-billable header; A66.9 is billable.
Registry fact
Can these codes be reported together?
Yes, when both are documented.A66.9 lists A27 under Excludes2: “leptospirosis (A27.-)”. Excludes2 marks distinct conditions that may both be reported when both are documented.
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.A27 is a non-billable header, but A66.9 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
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
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