Medicare carriers must use the following table to assign the proper TOS. Some procedures may have more than one applicable TOS. For claims received on or after April 3, 1995, CWF will produce alerts on codes with incorrect TOS designations. Effective July 3, 1995, CWF is rejecting codes with incorrect TOS designations. All future updates will be submitted via a Recurring Update Notification.
The only exceptions to this table are:
Surgical services billed for dates of service through December 31, 2007, containing the ASC facility service modifier SG must be reported as TOS F. Effective for services on or after January 1, 2008, the SG modifier is no longer applicable for Medicare services. ASC providers should discontinue applying the SG modifier on ASC facility claims. The indicator ‘F’ does not appear in the TOS table because its use depends upon claims submitted with POS 24 (ASC Facility) from an ASC (specialty 49). This became effective for dates of service January 1, 2008 and after.
Surgical services billed with an assistant-at-surgery modifier (80-82, AS,) must be reported with TOS 8. The 8 indicator does not appear on the TOS table because its use is dependent upon the use of the appropriate modifier. (See Pub. 100-04, Medicare Claims Processing Manual, Chapter 12, "Physician/Nonphysician Practitioner," for instructions on when assistant-at-surgery is allowable.)
Psychiatric treatment services that are subject to the outpatient mental health treatment limitation should be reported with TOS T.
TOS H appears in the list of descriptors. However, it does not appear in the table. In CWF, "H" is used only as an indicator for hospice. The carrier should not submit TOS H to CWF at this time.
For outpatient services, when a transfusion medicine code appears on a claim that also contains a blood product, the service is paid under reasonable charge at 80%, coinsurance and deductible apply. When transfusion medicine codes are paid under the clinical laboratory fee schedule pay at 100%, coinsurance and deductible do not apply.
NOTE: For injection codes with more than one possible TOS designation, use the following guidelines when assigning the TOS:
When the choice is L or 1,
Use TOS L when the drug is used related to ESRD; or
Use TOS 1 when the drug is not related to ESRD and is administered in the office.
When the choice is G or 1:
Use TOS G when the drug is an immunosuppressive drug; or
Use TOS 1 when the drug is used for other than immunosuppression.
When the choice is P or 1,
Use TOS P if the drug is administered through durable medical equipment (DME); or
Use TOS 1 if the drug is administered in the office.
The place of service or diagnosis may be considered when determining the appropriate TOS. The descriptors for each of the TOS codes listed in the following table are:
Type of Service Indicators
Assistant at Surgery
Other Medical Items or Services
High Risk Screening Mammography
Low Risk Screening Mammography
Ambulatory Surgical Center (Facility Usage for Surgical Services)
Hearing Items and Services
Monthly Capitation Payment for Dialysis
Lump Sum Purchase of DME, Prosthetics, Orthotics
Vision Items or Services
Rental of DME
Surgical Dressings or Other Medical Supplies
Outpatient Mental Health Treatment Limitation
Note: CPT®/HCPCS codes may be assigned one or more Type of Service code.