X35.XXXA vs X35.XXXD
X35.XXXA (Volcanic eruption, initial encounter) compared with X35.XXXD (Volcanic eruption, subsequent encounter), 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 20, 2026 · All releases and sources
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 differ in one word, “initial” (X35.XXXA) versus “subsequent” (X35.XXXD): X35.XXXA is “Volcanic eruption, initial encounter”; X35.XXXD is “Volcanic eruption, subsequent encounter”.
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.XXXD 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.XXXD 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 encounter | X35.XXXDVolcanic eruption, subsequent encounter | |
|---|---|---|
| Billing status | Billable | Billable |
| Classification | V00-Y99 — External Causes of Morbidity (V00-Y99) | V00-Y99 — External Causes of Morbidity (V00-Y99) |
| Definition | Volcanic eruption, initial encounter is a billable ICD-10-CM diagnosis code (X35.XXXA). | Volcanic eruption, subsequent encounter is a billable ICD-10-CM diagnosis code (X35.XXXD). |
| 7th character | The appropriate 7th character is to be added to code X35 | The 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