How ICD-10-CM, ICD-10-PCS, CPT and HCPCS fit on one claim
The four questions every claim answers
| Question | Code set |
|---|---|
| Why was the patient treated? | ICD-10-CM (diagnoses) |
| What was done during an inpatient stay? | ICD-10-PCS (facility claim) |
| What did the physician or outpatient department do? | CPT / HCPCS Level I (professional claim) |
| What supplies, drugs or transport were used? | HCPCS Level II, with modifiers |
Example 1: inpatient gallbladder surgery
A patient is admitted with acute cholecystitis and has a laparoscopic cholecystectomy. The facility claim carries ICD-10-CM K81.0 (acute cholecystitis) for the why and ICD-10-PCS 0FT44ZZ for the what. The surgeon's professional claim carries the same diagnosis but reports the operation with a CPT code instead - PCS never appears on a professional claim.
Example 2: office visit with an injection
A patient with Type 2 diabetes comes in for management and receives a B12 injection. The professional claim pairs ICD-10-CM E11.9 with a CPT evaluation-and-management code for the visit, plus HCPCS J3420 for the drug itself. The diagnosis justifies both lines; the HCPCS code is what gets the drug paid.
That division of labor is the whole system: diagnoses explain medical necessity, procedure codes describe the work, and supply codes make sure the things used along the way are not given away free. Look up any of them from the homepage search.