T23.409S — Corrosion of unspecified degree of unspecified hand, unspecified site, sequela

BillableUnspecified

Is T23.409S billable?

Yes, but T23.409S is an unspecified code. T23.409S is a valid, billable ICD-10-CM code for encounters from October 1, 2026 through September 30, 2027. However, T23.409S is an unspecified or catch-all code. Payers apply additional scrutiny to unspecified codes and many deny them when the medical record supports a more specific option, so check the documentation before selecting T23.409S — the more specific alternatives are listed below.

More specific alternatives

T23.409S at a glance

Code	T23.409S
Description	Corrosion of unspecified degree of unspecified hand, unspecified site, sequela
Billable	Yes
Code set	ICD-10-CM FY2027
Valid for encounters	October 1, 2026 – September 30, 2027
7th character "S"	sequela

What does the 7th character "S" mean in T23.409S?

In T23.409S, the 7th character S means sequela. The 7th character is required for T23.409S to be a valid, complete code.

Same condition, different episode of care — switch the 7th character:

Which MS-DRGs does T23.409S group to?

T23.409S sits in MDC 09 and helps define the logic of 2 MS-DRGs (version 44, FY2027). Which one a stay actually groups to also depends on procedures and secondary diagnoses.

604Trauma to the Skin, Subcutaneous Tissue and Breast with MCCmedical
605Trauma to the Skin, Subcutaneous Tissue and Breast without MCCmedical

How is T23.409S listed in the Alphabetic Index?

The Alphabetic Index lists these routes under T23.409, the nearest indexed parent of T23.409S. Use them to find the family, then select the specific code.

Corrosion › hand (injury) (acid) (caustic) (chemical) (lime) (external) (internal)

Code first — inherited from T23.4

The underlying condition below must be sequenced before T23.409S. T23.409S describes a manifestation and cannot be the principal or first-listed diagnosis.

(T51-T65) to identify chemical and intent

Use additional code — inherited from Chapter 19

Report an additional code alongside T23.409S to fully describe the condition. T23.409S is sequenced first.

code to identify any retained foreign body, if applicable (Z18.-)

Use additional code — inherited from T20-T25

Report an additional code alongside T23.409S to fully describe the condition. T23.409S is sequenced first.

code from category T31 or T32 to identify extent of body surface involved

Use additional code — inherited from T23.4

Report an additional code alongside T23.409S to fully describe the condition. T23.409S is sequenced first.

external cause code to identify place (Y92)

Excludes2 — not included here — inherited from Chapter 19

The conditions below are not part of T23.409S, but a patient may have both at the same time. When documentation supports it, T23.409S and the excluded code may both be reported.

birth trauma (P10-P15)
obstetric trauma (O70-O71)

How long has T23.409S existed?

T23.409S has been in ICD-10-CM since at least FY2016, the earliest fiscal year on record here.

Derived from the official order files for FY2016–FY2026. FY2017 and FY2020 publish no order file, so those years are not covered.