ICDcodes.org
FY2027

T21.64XA — Corrosion of second degree of lower back, initial encounter

Billable

Is T21.64XA billable?

Yes — T21.64XA is billable for FY2027. T21.64XA is a valid, billable ICD-10-CM code at the highest level of specificity in its branch. T21.64XA may be submitted for encounters from October 1, 2026 through September 30, 2027.

T21.64XA at a glance

CodeT21.64XA
DescriptionCorrosion of second degree of lower back, initial encounter
BillableYes
Code setICD-10-CM FY2027
Valid for encountersOctober 1, 2026 – September 30, 2027
7th character "A"initial encounter

What does the 7th character "A" mean in T21.64XA?

In T21.64XA, the 7th character A means initial encounter. The 7th character is required for T21.64XA to be a valid, complete code.

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

Which MS-DRGs does T21.64XA group to?

T21.64XA sits in MDC 22 and helps define the logic of 1 MS-DRG (version 44, FY2027). Which one a stay actually groups to also depends on procedures and secondary diagnoses.

  • 935Non-Extensive Burnsmedical

How is T21.64XA listed in the Alphabetic Index?

The Alphabetic Index lists these routes under T21.64, the nearest indexed parent of T21.64XA. Use them to find the family, then select the specific code.

  • Corrosion › back › second degree (injury) (acid) (caustic) (chemical) (lime) (external) (internal)

Code first — inherited from T21.6

The underlying condition below must be sequenced before T21.64XA. T21.64XA 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 T21.64XA to fully describe the condition. T21.64XA 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 T21.64XA to fully describe the condition. T21.64XA is sequenced first.

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

Use additional code — inherited from T21.6

Report an additional code alongside T21.64XA to fully describe the condition. T21.64XA 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 T21.64XA, but a patient may have both at the same time. When documentation supports it, T21.64XA and the excluded code may both be reported.

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

Excludes2 — not included here — inherited from T21

The conditions below are not part of T21.64XA, but a patient may have both at the same time. When documentation supports it, T21.64XA and the excluded code may both be reported.

  • burns and corrosion of axilla (T22.- with fifth character 4)
  • burns and corrosion of scapular region (T22.- with fifth character 6)
  • burns and corrosion of shoulder (T22.- with fifth character 5)

How long has T21.64XA existed?

T21.64XA 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.