As the world continues to grow, so too will the need for medical services in all corners of the world. Unfortunately, some areas are so remote or understaffed that there is no reasonable way for healthcare professionals to treat every patient in person. Thankfully, consultations over the phone or internet–known collectively as telehealth services–can help bring the needed care to rural locations.

As with all procedures, the Centers for Medicare and Medicaid Services (CMS) have strict rules that must be followed for these remote visits to be counted as telehealth services. For starters, only certain locations are eligible in the first place; in order for a Medicare patient to receive telehealth services, he or she must be in either in a county not included in a metropolitan statistical area, or in an originating zone that falls within a Health Professional Shortage Area. Keep in mind that any site which helped with federal telehealth demonstration prior to 2001 is automatically considered an origin site.

From there, only a handful of codes are qualified to be performed remotely. Unsurprisingly, telehealth services work best for diagnoses that involve more discussion than hands-on treatment; as such, minor mental treatments (such as psychotherapy as an E&M service) and their accompanying diagnoses (such as an annual depression screening) are some of the most common telehealth conditions.

Additionally, there are a few extra protocols to keep in mind. The provider and the patient must be in continuous two-way communication; unsynced call-and-response lines are only allowed in a few select demonstration programs in Hawaii and Alaska. Telehealth services also require their own modifier. By affixing “GT” to the end of a code, you certify that it was performed via interactive audio and video telecommunications systems.

When learning these criteria, remember that CMS issues updates every year, so what is true now may not be true in a few months. Furthermore, telehealth services can have entirely different rules under private insurers, so be sure to consult the payer-specific guidelines before making any final decisions.