A surgical sponge is provided, having a radiofrequency (RF) tag positioned interior thereto. The RF tag has a base layer with at least one tab projecting from an outer perimeter of thereof. The RF tag has a first protective layer with at least one tab projecting from the outer perimeter of the RF tag and generally aligned with the at least one tab of the base layer and an RF identifier laminated between the base layer and the first protective layer. The RF identifier has an antenna, and an electrically responsive member. The antenna can be a metal foil loop antenna etched on to the base layer. The RF identifier can include additional metal foil provided on the base layer when the metal foil loop antenna is etched on to the base layer, the additional metal foil configured to enhance x-ray opacity of the sponge.