S21.95XA
Open bite of unspecified part of thorax, initial encounter
S21.95XA (also written S2195XA) is a billable ICD-10-CM diagnosis code for open bite of unspecified part of thorax, initial encounter. It is part of the FY2027 code set, effective October 1, 2026. It is one of the 288 codes in category S21 (Open wound of thorax). The Alphabetic Index lists it under 1 entry. Its 7th character, A, means initial encounter. Its coding notes include a Use additional code instruction, a Code also instruction, 2 Excludes1 entries and 13 Excludes2 entries.
7th character
Category S21 requires a 7th character. S21.95 has only 5 characters, so a placeholder X fills the 6th position.
Guidelines tips
From the FY2027 Official Guidelines. ICD10Ref adds no rules of its own.
The 7th character depends on whether the patient is in active treatment, not on who sees the patient. An aftercare Z code is not used for injury aftercare.
Each injury gets its own code unless a combination code exists, with the most serious injury first. Superficial injuries at the same site as a more severe injury are not coded. Injuries during medical care are coded as complications.
Use additional code
Add the listed code as a secondary code, if known.
Also from chapter/block level (1 note)
- code to identify any retained foreign body, if applicable (Z18.-)
Code also
Two codes may be needed to describe the condition. This note gives no sequencing order.
Excludes1
Not coded here. The listed conditions generally should not be reported together.
Excludes2
Not included here. Both codes may be reported if the patient has both conditions.
Also from chapter/block level (13 notes)
- burns and corrosions (T20-T32)
- effects of foreign body in bronchus (T17.5)
- effects of foreign body in esophagus (T18.1)
- effects of foreign body in lung (T17.8)
- effects of foreign body in trachea (T17.4)
- frostbite (T33-T34)
- injuries of axilla
- injuries of clavicle
- injuries of scapular region
- injuries of shoulder
- insect bite or sting, venomous (T63.4)
- birth trauma (P10-P15)
- obstetric trauma (O70-O71)
Care settings
How CMS programs treat this code. These are CMS claim edits and list entries, not coverage or eligibility rules.
Hospital CC
Counts as a complication or comorbidity (CC) when reported as a secondary diagnosis on an inpatient claim. It does not count when the principal diagnosis is one of the 95 codes in its exclusion list. Some MS-DRGs also ignore a CC or MCC that defines the DRG.
Source: CMS MS-DRG Definitions Manual v44, effective October 1, 2026, Appendix CIncludes
Further defines or gives examples of the content of the category.
Also from chapter/block level (3 notes)
- injuries of breast
- injuries of chest (wall)
- injuries of interscapular area
Notes
Also from chapter/block level (2 notes)
- Use secondary code(s) from Chapter 20, External causes of morbidity, to indicate cause of injury. Codes within the T section that include the external cause do not require an additional external cause code
- The chapter uses the S-section for coding different types of injuries related to single body regions and the T-section to cover injuries to unspecified body regions as well as poisoning and certain other consequences of external causes.
Alphabetic Index terms
Terms the official Alphabetic Index lists for S21.95. This code adds the 7th character. 1 entry