What are Place of Service (POS) codes in medical billing?

Place of Service codes determine reimbursement because Medicare and commercial payers pay different rates for the same CPT code depending on where it was performed. The site-of-service differential is real money: an E/M visit billed under POS 11 (office) typically pays the full Physician Fee Schedule amount, while the same visit under POS 22 (on-campus outpatient hospital) pays the facility-based rate, often 30 to 40 percent lower. Below is the working list of POS codes most healthcare practices use. POS 02 — Telehealth Provided Other Than in Patient's Home (post-PHE rules apply). POS 10 — Telehealth Provided in Patient's Home (separate code since January 2022). POS 11 — Office (the most common, default for in-clinic care). POS 12 — Home (visits to patient's residence). POS 19 — Off Campus Outpatient Hospital (hospital-affiliated outpatient clinic not on the main hospital campus). POS 20 — Urgent Care Facility. POS 21 — Inpatient Hospital. POS 22 — On Campus Outpatient Hospital. POS 23 — Emergency Room. POS 24 — Ambulatory Surgical Center. POS 31 — Skilled Nursing Facility. POS 32 — Nursing Facility. POS 49 — Independent Clinic. POS 50 — Federally Qualified Health Center. POS 71 — State or Local Public Health Clinic. POS 72 — Rural Health Clinic. POS 81 — Independent Laboratory. The most common billing errors involve telehealth (POS 02 vs POS 10 since 2022), confusing POS 19 (off-campus hospital outpatient) with POS 22 (on-campus), and using POS 11 when the practice is actually a hospital outpatient department. CMS publishes the full list of POS codes and updates it annually; cross-check the active code set every January.