S06.820A vs S06.820D

S06.820A (Injury of left internal carotid artery, intracranial portion, not elsewhere classified without loss of consciousness, initial encounter) compared with S06.820D (Injury of left internal carotid artery, intracranial portion, not elsewhere classified without loss of consciousness, subsequent encounter), from the official CMS tabular data. S06.820A and S06.820D code the same injury at a different phase of treatment.

Relationship

Review

Encounter relationship

S06.820A

Initial encounter

Injury of left internal carotid artery, intracranial portion, not elsewhere classified without loss of consciousness, initial encounter

↔

S06.820D

Subsequent encounter

Injury of left internal carotid artery, intracranial portion, not elsewhere classified without loss of consciousness, 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. S06.820A and S06.820D 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

	S06.820AInjury of left internal carotid artery, intracranial portion, not elsewhere classified without loss of consciousness, initial encounter	S06.820DInjury of left internal carotid artery, intracranial portion, not elsewhere classified without loss of consciousness, subsequent encounter
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	Injury of left internal carotid artery, intracranial portion, not elsewhere classified without loss of consciousness, initial encounter is a billable ICD-10-CM diagnosis code (S06.820A).	Injury of left internal carotid artery, intracranial portion, not elsewhere classified without loss of consciousness, subsequent encounter is a billable ICD-10-CM diagnosis code (S06.820D).
7th character	The appropriate 7th character is to be added to each code from category S06, except as noted below	The appropriate 7th character is to be added to each code from category S06, except as noted below
Includes	traumatic brain injury injuries of ear injuries of eye injuries of face [any part]	traumatic brain injury injuries of ear injuries of eye injuries of face [any part]
Use additional code	code, if applicable, to identify mild neurocognitive disorders due to known physiological condition (F06.7-)	code, if applicable, to identify mild neurocognitive disorders due to known physiological condition (F06.7-)

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