The presence or absence of objects tagged with transponders may be determined in an environment in which medical procedures are performed via an interrogation and detection system which includes a controller and a plurality of antennas positioned along a patient support structure. The antennas may be positioned along an operating table, bed, mattress or pad, sheet, or may be positioned on a drape, or shade. Respective antennas may successively be activated to transmit interrogation signals. Multiple antennas may be monitored for responses from transponders to the interrogation signals. For example, all antennas other than the antenna that transmitted the most recent interrogation signal may be monitored. Antennas may be responsive to force, a signal indicative of such force being produced. A wireless physiological condition monitor may detect patient physiological conditions and wirelessly transmit signals indicative of such.
