What COC is
The Certified Outpatient Coder (COC) credential, from AAPC, focuses specifically on facility-side outpatient coding — hospital outpatient departments and ambulatory surgery centers (ASCs). This is a different claim and a different rule set than the physician's own professional coding for the same visit.
The outpatient facility coding flow
COC covers facility-side outpatient coding — the hospital or ASC's claim, not the physician's separate professional claim.
Key concepts unique to outpatient facility coding
| Concept | What it means |
|---|---|
| APCs | Ambulatory Payment Classifications — the payment grouping system Medicare uses for hospital outpatient services, similar in spirit to inpatient DRGs |
| OCE edits | Outpatient Code Editor — automated checks that flag code combinations that can't be billed together |
| UB-04 | The standard facility claim form (institutional claim) |
| Modifier -25 / -59 | Facility-side modifiers with their own specific rules, distinct from how they're used on a physician claim |
Exam format
| Detail | What to expect |
|---|---|
| Administered by | AAPC |
| Focus | Hospital outpatient and ASC facility coding |
| Code sets | CPT, HCPCS Level II, ICD-10-CM (diagnosis only — no ICD-10-PCS) |
Who should pursue COC
Coders aiming for a job specifically in a hospital outpatient department, ASC, or facility billing office — as opposed to a physician practice (CPC) or inpatient hospital coding (CIC).
How it compares to CPC and CIC
| CPC | COC | CIC | |
|---|---|---|---|
| Claim type | Professional (physician) | Facility, outpatient | Facility, inpatient |
| Setting | Physician office | Hospital outpatient / ASC | Hospital inpatient |
| Procedure coding | CPT/HCPCS | CPT/HCPCS | ICD-10-PCS |
Ready for the inpatient side of facility coding?
Read: Introduction to CIC →