“See” vs “See Also” in the Alphabetic Index: When You Must Follow the Cross-Reference
Part ofCoding fundamentals · step 2 of 6 · Read next“Other” vs “Unspecified,” NEC vs NOS: Which Residual Code Fits the Record
Editorial explanation — not an official CMS/CDC rule. Official coding instructions and source material are identified below. How to read the labels
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
Quick answer · MedCoder editorial
A “see” cross-reference must be followed — the term you are on has no code, and the correct code is under the term it names. A “see also” cross-reference is optional: the term you are on may already give the code, and the other term is offered in case it holds additional entries you need.
Jump to the decision rule ↓What decides the answer?
- Whether the Index entry says “see” (mandatory) or “see also” (follow it when the subterm is missing)
- The exact term the provider used, which selects the main term
- Verification of any Index code in the Tabular before assignment (I.B.1)
Why it matters
The rule
Official source“The ‘see’ instruction following a main term in the Alphabetic Index indicates that another term should be referenced. It is necessary to go to the main term referenced with the ‘see’ note to locate the correct code.”
“A ‘see also’ instruction following a main term in the Alphabetic Index instructs that there is another main term that may also be referenced that may provide additional Alphabetic Index entries that may be useful. It is not necessary to follow the ‘see also’ note when the original main term provides the necessary code.”
The difference is whether the term you are on carries a code. A “see” entry has none — it is a signpost. A “see also” entry usually has one, and the cross-reference is a second place to look when the subterm you need is not listed here.
Examples
Both forms inside one main term
The Index entry for fractures shows both. “Fracture, burst — see Fracture, traumatic, by site” is a “see”: burst fracture has no code under that term, and the coder must go to “Fracture, traumatic” and find the site. “Fracture, insufficiency — see Fracture, pathological, by site” and “Fracture, chronic — see Fracture, pathological, by site” work the same way.
“Fracture, traumatic … (see also Fracture, pathological) T14.8” is a “see also”: the term already provides a default code and a full site list, and the cross-reference exists because a fracture documented as pathological is indexed under the other term. The reciprocal “Fracture, pathological (see also Fracture, traumatic) M84.40” is the same device pointing back. Neither “see also” needs to be followed when the entry in hand gives the code.
A “see” can also sit under a subterm. “Cholecystitis” carries the default K81.9 and then, under “with calculus, stones in gallbladder,” the instruction “see Calculus, gallbladder, with cholecystitis” — the code for that combination lives under the calculus term, and the coder must go there.
Decision rule
Decision framework
| IF the Index entry says… | THEN… |
|---|---|
| “see [term]” | Go to that term — the code is only there |
| “see also [term]” and the current entry gives the code you need | Use it; the cross-reference is optional |
| “see also [term]” and the subterm you need is not under the current entry | Follow it — the other term may list it |
| Any code found in the Index | Verify it in the Tabular before assigning it (Section I.B.1) |
How to apply it
How to apply the rule
- Locate the main term in the Alphabetic Index.
- “See”: go to the referenced term; the code is only there.
- “See also”: use the code at the current term if it fits; go to the referenced term only if the subterm you need is not listed.
- Verify the code in the Tabular before assigning it (I.B.1).
Common mistakes
Common mistakes
- Assigning a code from a term that carries only a “see” instruction — it has no code.
- Following every “see also” even when the current entry already gives the code.
- Coding from the Index without verifying in the Tabular.
Documentation matters
Documentation that changes the coding
- The exact term the provider used — it determines the main term and which cross-reference applies.
- Modifiers (cause, site, acuity) that select the subterm under the referenced term.
FAQ
Do I have to follow a “see” cross-reference?
Yes. Section I.A.16 says it is necessary to go to the main term referenced with the “see” note to locate the correct code — the term carrying the “see” has no code of its own.
Do I have to follow a “see also” cross-reference?
Only when the term you are on does not provide the code you need. The Guidelines say it is not necessary to follow the “see also” note when the original main term provides the necessary code.
Can I assign a code straight from the Alphabetic Index?
No. Section I.B.1 says to locate the term in the Index and then verify the code in the Tabular List, which alone shows laterality, 7th characters and the instructional notes.
Why does “Fracture, traumatic” point to “Fracture, pathological” and back?
Because each is a “see also”: both terms carry their own codes and site lists, and the cross-references exist so a coder who starts under the wrong cause can find the other family. Neither reference has to be followed when the entry in hand gives the code.
Code set release
This guide was verified against ICD-10-CM FY2027, effective October 1, 2026.
Compare these pairs
Authoritative sources
Applies to FY2027 ICD-10-CM
Verified against the FY 2027 ICD-10-CM Official Guidelines (Section I.A.16) and the FY 2027 Alphabetic Index main terms “Fracture, burst,” “Fracture, traumatic,” “Fracture, pathological” and “Cholecystitis.”
- ICD-10-CM Official Guidelines for Coding and Reporting, FY 2027 (Section I.A.16, “See” and “See Also”)
- FY 2027 ICD-10-CM Alphabetic Index to Diseases and Injuries (Fracture; Cholecystitis)
Official guidance cited
The Official Guidelines sections this guide quotes or applies, by heading. Passages set as quotations above are the sections’ own words; the surrounding text is MedCoder’s reading of them.
- Section I.B.1 — Locating a code in the ICD-10 -CM
- Section I.A.16 — “See” and “See Also”
Passages set as quotations are verbatim official text from the sources listed. Surrounding explanation, decision tables and examples are MedCoder’s editorial reading of those sources and are not official statements. Examples are illustrative; they assign no code to any real patient.
Coder Takeaway: “See” is mandatory — the code lives under the other term. “See also” is optional — follow it only when the current term does not give the code. Verify in the Tabular either way.
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Applicable code set: FY2027. Published September 3, 2026; last updated October 1, 2026; last reviewed October 1, 2026.