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X35.XXXA vs X35.XXXS

X35.XXXA (Volcanic eruption, initial encounter) compared with X35.XXXS (Volcanic eruption, sequela), from the official CMS tabular data.

Summary

No tabular note links these codes. Both belong to category X35, and nothing in the tabular list prevents reporting each when it is documented.

Registry fact
What is different?

Title wording.The titles share “Volcanic eruption”; X35.XXXA says “initial encounter” where X35.XXXS says “sequela”.

Registry fact

Can these codes be reported together?

No instruction prevents it.No note in either entry names the other. Both belong to category X35; each may be reported when its own documentation is present.

Registry fact

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. X35.XXXA carries 1 Excludes2 note and X35.XXXS carries 1 Excludes2 note covering other codes; the side-by-side table quotes them.

Official rule

Is one more specific?

No.Neither is a subdivision of the other, and neither title is the unspecified form; they describe different conditions within category X35.

Registry fact

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?

Yes, when each is documented. X35.XXXA and X35.XXXS both belong to category X35.

No Excludes1/Excludes2 relationship exists between these codes in the official tabular list. The code titles state what each one covers, and the documentation decides which applies.

Side by side

X35.XXXAVolcanic eruption, initial encounterX35.XXXSVolcanic eruption, sequela
Billing statusBillableBillable
ClassificationV00-Y99 — External Causes of Morbidity (V00-Y99)V00-Y99 — External Causes of Morbidity (V00-Y99)
DefinitionVolcanic eruption, initial encounter is a billable ICD-10-CM diagnosis code (X35.XXXA).Volcanic eruption, sequela is a billable ICD-10-CM diagnosis code (X35.XXXS).
7th characterThe appropriate 7th character is to be added to code X35The appropriate 7th character is to be added to code X35
Excludes2
tidal wave (tsunami) due to volcanic eruption (X37.41)
tidal wave (tsunami) due to volcanic eruption (X37.41)

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.

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