Question: We hired a locum tenens for two weeks. Do we code the same for the replacement physician as for a full-time oncologist? New York Subscriber Answer: Private payer rules may vary, but for Medicare patients, append modifier Q6 (Service furnished under a fee-for-time compensation arrangement by a substitute physician…) to each procedure code on the temporary doctor’s Medicare claims. Bill with the national provider identifier (NPI) of the physician the locum is replacing. Your two-week arrangement falls well inside Medicare’s 60-day limit for a locum tenens. Just be aware, a substitute physician may not provide services to Medicare patients for more than 60 days, according to the Medicare Claims Processing Manual, Chapter 1, Section 30.2.11. (See additional details in the manual, online at www.cms.hhs.gov/manuals/downloads/clm104c01.pdf.) Private payers vary: Before using modifier Q6 for a non-Medicare patient, check with the commercial payer. Some will follow the Medicare locum tenens guidelines, but do not assume all commercial payers will want modifier Q6. Private payers’ rules regarding substitute physicians can differ from Medicare’s. Definition: A locum tenens arrangement describes a one-way exchange between physicians, in which your oncologist or hematologist retains a substitute physician (the locum tenens) to take over the practice temporarily and pays the substitute physician a fixed amount per diem or similar fee-for-time structure. Reasons for hiring a locum tenens may include the regular physician needing time away for illness, pregnancy, vacation, or continuing medical education.