HCPCS 'S' Modifiers (21)
| Code | Description |
| SA | Nurse practitioner rendering service in collaboration with a physician |
| SB | Nurse midwife |
| SC | Medically necessary service or supply |
| SD | Services provided by registered nurse with specialized, highly technical home infusion training |
| SE | State and/or federally-funded programs/services |
| SF | Second opinion ordered by a professional review organization (pro) per section 9401, p.l. 99-272 (100% reimbursement - no medicare deductible or coinsurance) |
| SG | Ambulatory surgical center (asc) facility service |
| SH | Second concurrently administered infusion therapy |
| SJ | Third or more concurrently administered infusion therapy |
| SK | Member of high risk population (use only with codes for immunization) |
| SL | State supplied vaccine |
| SM | Second surgical opinion |
| SN | Third surgical opinion |
| SQ | Item ordered by home health |
| SS | Home infusion services provided in the infusion suite of the iv therapy provider |
| ST | Related to trauma or injury |
| SU | Procedure performed in physician's office (to denote use of facility and equipment) |
| SV | Pharmaceuticals delivered to patient's home but not utilized |
| SW | Services provided by a certified diabetic educator |
| SY | Persons who are in close contact with member of high-risk population (use only with codes for immunization) |
| SZ | Habilitative services Terminated: December 31, 2017 |