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S86.109A vs S86.109D

S86.109A (Unspecified injury of other muscle(s) and tendon(s) of posterior muscle group at lower leg level, unspecified leg, initial encounter) compared with S86.109D (Unspecified injury of other muscle(s) and tendon(s) of posterior muscle group at lower leg level, unspecified leg, subsequent encounter), from the official CMS tabular data. S86.109A and S86.109D code the same injury at a different phase of treatment.

Relationship

Review

Encounter relationship

S86.109A
Initial encounter
Unspecified injury of other muscle(s) and tendon(s) of posterior muscle group at lower leg level, unspecified leg, initial encounter
S86.109D
Subsequent encounter
Unspecified injury of other muscle(s) and tendon(s) of posterior muscle group at lower leg level, unspecified leg, subsequent encounter

Same underlying diagnosis, different encounter phase.

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

Can these codes be reported together?

Same injury, other encounter phase. S86.109A and S86.109D 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.

Side by side

S86.109AUnspecified injury of other muscle(s) and tendon(s) of posterior muscle group at lower leg level, unspecified leg, initial encounterS86.109DUnspecified injury of other muscle(s) and tendon(s) of posterior muscle group at lower leg level, unspecified leg, subsequent encounter
Billing statusBillableBillable
ClassificationS00-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)
DefinitionUnspecified injury of other muscle(s) and tendon(s) of posterior muscle group at lower leg level, unspecified leg, initial encounter is a billable ICD-10-CM diagnosis code (S86.109A).Unspecified injury of other muscle(s) and tendon(s) of posterior muscle group at lower leg level, unspecified leg, subsequent encounter is a billable ICD-10-CM diagnosis code (S86.109D).
7th characterThe appropriate 7th character is to be added to each code from category S86The appropriate 7th character is to be added to each code from category S86

Derived from the official CMS ICD-10-CM tabular data (FY2026). Not billing advice; verify sequencing rules for the encounter. All data sources