Chapter 12 — Diseases of the Skin and Subcutaneous Tissue
Pressure ulcer stage and non-pressure ulcer severity — unstageable versus unspecified, healed versus healing, and the two-code rule when an ulcer worsens in hospital.
Chapter 12 is about staging — and about the difference between a stage that cannot be determined and a stage that was never written down. Pressure ulcers use L89 with the site and stage built into the code; non-pressure chronic ulcers follow parallel rules for severity. The one rule that surprises people: an ulcer that progresses during an inpatient stay needs two codes.
Pressure ulcer stages#
| Situation | Assign |
|---|---|
Category L89 | Identifies the site and the stage of the pressure ulcer. ICD-10-CM classifies pressure ulcer stages based on severity: stages 1–4, deep tissue pressure injury, unspecified stage, and unstageable |
| Multiple pressure ulcers | Assign as many codes from L89 as needed to identify all the pressure ulcers the patient has |
Unstageable — L89.--0 | The stage cannot be clinically determined, for example the ulcer is covered by eschar or has been treated with a skin or muscle graft. Assignment is based on the clinical documentation |
Unspecified stage — L89.--9 | There is no documentation regarding the stage of the pressure ulcer |
| Stage revealed after debridement during an encounter | Assign only the code for the stage revealed following debridement |
Pressure-induced deep tissue damage or deep tissue pressure injury — L89.--6 | Assign only the appropriate code for pressure-induced deep tissue damage |
| Documented as completely healed at the time of admission | NEVER No code is assigned |
| Documented as healing | Assign the appropriate pressure ulcer stage code based on the documentation. If the documentation does not provide the stage of the healing ulcer, assign the code for unspecified stage |
| Unclear whether the patient has a current (new) ulcer or is being treated for a healing ulcer | QUERY Query the provider |
| Present on admission but healed at the time of discharge | Assign the code for the site and stage at the time of admission |
| Admitted at one stage and it progresses to a higher stage during the admission | ALWAYS Two separate codes: one for the site and stage on admission, and a second for the same ulcer site at the highest stage reported during the stay |
| Stage documented in clinical terms not found in the Alphabetic Index, with no documentation of the stage itself | QUERY Query the provider |
Non-pressure chronic ulcers#
| Situation | Assign |
|---|---|
| Documented as completely healed at the time of admission | NEVER No code is assigned |
| Documented as healing | The appropriate non-pressure ulcer code based on the documentation. If the severity of the healing ulcer is not documented, assign the code for unspecified severity |
| Unclear whether current (new) or healing | QUERY Query the provider |
| Present on admission but healed at the time of discharge | The code for the site and severity at the time of admission |
| Admitted at one severity level and it progresses to a higher level during the admission | ALWAYS Two codes: the site and severity on admission, and the same site at the highest severity level reported during the stay |
Both the pressure ulcer stage and the depth of non-pressure chronic ulcers are on the Section I.B.14 list of items that may be coded from the documentation of a clinician who is not the patient's provider — typically a wound care nurse. The underlying diagnosis must still come from the provider, and conflicting documentation is a query.
Practice questions#
Q1A patient is admitted with a stage 2 pressure ulcer of the sacrum. During the admission it deteriorates to stage 4. What is assigned?
- AOne code for stage 4
- BOne code for stage 2
- CTwo codes: the sacral ulcer at stage 2 and the sacral ulcer at stage 4
- DOne code for unstageable
Show answer & rationale
Correct answer: C. Two codes: the sacral ulcer at stage 2 and the sacral ulcer at stage 4
Rationale. Guideline I.C.12.a.6 states that if a patient is admitted to an inpatient hospital with a pressure ulcer at one stage and it progresses to a higher stage, two separate codes should be assigned: one code for the site and stage of the ulcer on admission and a second code for the same ulcer site and the highest stage reported during the stay. Contrast this with dementia and glaucoma, where only the highest level is coded.
Q2A pressure ulcer is covered by eschar and the provider documents that the stage cannot be determined. Which code is assigned?
- A
L89.--9unspecified stage - B
L89.--0unstageable - C
L89.--6deep tissue damage - DNo code until the eschar is debrided
Show answer & rationale
Correct answer: B. L89.--0 unstageable
Rationale. Guideline I.C.12.a.2 states that assignment of the code for unstageable pressure ulcer, L89.--0, is based on the clinical documentation, and that these codes are used for pressure ulcers whose stage cannot be clinically determined, giving eschar and treatment with a skin or muscle graft as the examples. It is not to be confused with the codes for unspecified stage, L89.--9, which are used when there is no documentation regarding the stage.
Q3An unstageable pressure ulcer is debrided during the encounter, revealing a stage 3 ulcer. What is assigned?
- AThe unstageable code and the stage 3 code
- BOnly the code for the stage revealed following debridement
- COnly the unstageable code
- DThe unspecified stage code
Show answer & rationale
Correct answer: B. Only the code for the stage revealed following debridement
Rationale. Guideline I.C.12.a.2 states that if, during an encounter, the stage of an unstageable pressure ulcer is revealed after debridement, assign only the code for the stage revealed following debridement. Only one code is assigned, and it is the revealed stage.
Q4The documentation states the pressure ulcer was completely healed at the time of admission. What is assigned?
- AThe stage at the time it was last active
- BThe unspecified stage code
- CNo code
- DA personal history code
Show answer & rationale
Correct answer: C. No code
Rationale. Guideline I.C.12.a.4 states plainly that no code is assigned if the documentation states that the pressure ulcer is completely healed at the time of admission. Guideline I.C.12.b.1 applies the identical rule to non-pressure chronic ulcers. Ulcers documented as healing, by contrast, are coded at the documented stage or severity, or unspecified if none is given.
Q5A pressure ulcer was present on admission at stage 2 and is completely healed by discharge. What is assigned?
- ANo code, because it healed
- BThe code for the site and stage of the ulcer at the time of admission
- CA personal history code
- DThe unspecified stage code
Show answer & rationale
Correct answer: B. The code for the site and stage of the ulcer at the time of admission
Rationale. Guideline I.C.12.a.5 states that for ulcers that were present on admission but healed at the time of discharge, assign the code for the site and stage of the pressure ulcer at the time of admission. The mirror rule for non-pressure chronic ulcers appears at I.C.12.b.2. Note the contrast with an ulcer already healed at the time of admission, which gets no code at all.
Scenarios#
A nursing-home resident is admitted with a stage 3 pressure ulcer of the left heel, a stage 2 pressure ulcer of the right buttock, and pressure-induced deep tissue damage of the sacrum. The wound care nurse documents all three; the attending documents “multiple pressure ulcers”.
Show coded answer & rationale
| Seq | Code | Description |
|---|---|---|
| 1 | L89.623 | Pressure ulcer of left heel, stage 3 — verify in the Tabular List |
| 2 | L89.312 | Pressure ulcer of right buttock, stage 2 — verify in the Tabular List |
| 3 | L89.156 | Pressure-induced deep tissue damage of sacral region — verify in the Tabular List |
Rationale. Guideline I.C.12.a.1 directs that as many codes from category L89 as needed be assigned to identify all the pressure ulcers the patient has, and cross-references Section I.B.14 for staging documented by a clinician other than the provider. Guideline I.C.12.a.7 requires that for pressure-induced deep tissue damage only the appropriate L89.--6 code be assigned — no separate stage code. All three would carry POA indicator Y, and the admission skin assessment is the supporting documentation.
Guideline: Section I.C.12.a.1, I.C.12.a.7, I.B.14; Appendix I
A patient is admitted for an unrelated condition. The record documents a “healing sacral pressure ulcer” with no stage recorded anywhere, and no clinician is available to clarify before coding.
Show coded answer & rationale
| Seq | Code | Description |
|---|---|---|
| 1 | Reason for admission | the condition that occasioned the admission, as principal diagnosis |
| 2 | L89.159 | Pressure ulcer of sacral region, unspecified stage — verify in the Tabular List |
Rationale. Guideline I.C.12.a.5 states that pressure ulcers described as healing should be assigned the appropriate pressure ulcer stage code based on the documentation, and that if the documentation does not provide information about the stage of the healing pressure ulcer, the appropriate code for unspecified stage is assigned. The same guideline directs a query if it is unclear whether the patient has a current (new) ulcer or is being treated for a healing one. Section I.B.18 confirms that an unspecified code is the correct choice where the record genuinely lacks the detail.
Guideline: Section I.C.12.a.5, I.B.18
A diabetic patient is admitted with a non-pressure chronic ulcer of the right lower leg limited to breakdown of skin. During the admission it progresses to necrosis of muscle.
Show coded answer & rationale
| Seq | Code | Description |
|---|---|---|
| 1 | E11.621 | Type 2 diabetes mellitus with foot ulcer, or the applicable diabetes with skin ulcer code, sequenced per the Tabular List |
| 2 | L97.- | Non-pressure chronic ulcer of right lower leg with breakdown of skin — severity on admission |
| 3 | L97.- | Non-pressure chronic ulcer of the same site with necrosis of muscle — the highest severity level reported during the stay |
Rationale. Guideline I.C.12.b.3 requires two separate codes when a patient is admitted with a non-pressure ulcer at one severity level and it progresses to a higher severity level: one for the site and severity on admission, and a second for the same site at the highest severity reported during the stay. The diabetes link follows Section I.A.15, because diabetes and ulcer are linked by “with” in the Alphabetic Index, and the Tabular List instructional notes at the E11.6- subcategory direct the additional L97 code and its sequence.
Guideline: Section I.C.12.b.3, I.A.15, I.B.1
Primary sources#
- ICD-10-CM Official Guidelines for Coding and Reporting, FY 2027CMS — the source document for every page on this site (effective 1 Oct 2026)
- NCHS ICD-10-CM files — Tabular List, Index, POA exempt listOfficial code files, addenda and the list of codes exempt from POA reporting
- ICD-10 Coordination and Maintenance CommitteeWhere code proposals are debated; agendas, summaries and meeting materials
- CMS ICD-10 homeCode sets, transition guidance and Medicare coding policy
- AHA Coding ClinicOfficial coding advice from the AHA Central Office — subscription required
- HHS OIG Work PlanActive audit topics — useful for prioritising internal coding audits
- MEDESUN Medical Coding AcademyTraining, credential preparation and audit services by the author