Patients having an HST are sent home to sleep with specialized equipment and instructions. The person puts on the equipment and self-administers the test. The equipment is a very simplified breathing monitor that tracks breathing, oxygen levels, and breathing effort while worn. Soon after the HST, equipment is returned, and data read from the monitors. Some HSTs currently do not fully capture what is monitored with a polysomnography test in an overnight lab, but technology in this area improves regularly.