S20.179A vs S20.179S

S20.179A (Other superficial bite of breast, unspecified breast, initial encounter) compared with S20.179S (Other superficial bite of breast, unspecified breast, sequela), from the official CMS tabular data. S20.179A and S20.179S code the same injury at a different phase of treatment. MedCoder-derived

Can these codes be reported together?

Review

Encounter relationship

S20.179A

Initial encounter

Other superficial bite of breast, unspecified breast, initial encounter

↔

S20.179S

Sequela

Other superficial bite of breast, unspecified breast, sequela

What we found

Same injury, other encounter phase.S20.179A and S20.179S code the same injury at a different phase of treatment, set by the 7th character.

The 7th character records the type of care given at the encounter being coded (ICD-10-CM Official Guidelines, Section I.C.19.a), so one encounter takes one of these, not both.

What to review

Use the 7th character that matches the encounter being coded (initial, subsequent or sequela); one encounter takes one of them.

Guide: 7th characters: initial, subsequent, sequela Check these on a claim

Why it matters

The 7th character records the phase of care for the encounter being coded, so a single encounter takes one of these characters, not several. Review whether both phases belong on the same episode of care.

Source / rule

ICD-10-CM Official Guidelines, Section I.C.19.a

Side by side

	S20.179AOther superficial bite of breast, unspecified breast, initial encounter	S20.179SOther superficial bite of breast, unspecified breast, sequela
Billing status	Billable	Billable
Classification	S00-T88 — Injury, Poisoning and Certain Other Consequences of External Causes (S00-T88)	S00-T88 — Injury, Poisoning and Certain Other Consequences of External Causes (S00-T88)
Definition	Other superficial bite of breast, unspecified breast, initial encounter is a billable ICD-10-CM diagnosis code (S20.179A).	Other superficial bite of breast, unspecified breast, sequela is a billable ICD-10-CM diagnosis code (S20.179S).
7th character	The appropriate 7th character is to be added to each code from category S20	The appropriate 7th character is to be added to each code from category S20
Includes	injuries of breast injuries of chest (wall) injuries of interscapular area	injuries of breast injuries of chest (wall) injuries of interscapular area
Excludes1	open bite of breast (S21.05-)	open bite of breast (S21.05-)
Excludes2	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)	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)

Notes are the code’s own tabular entry, quoted as published. A note that names the other code is the one the verdict above rests on.

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Derived from the official CMS ICD-10-CM tabular data (FY2026). A coding-rule comparison, not billing advice: payer-specific edits and medical-necessity policy are outside its scope. All data sources