The presence of a sponge on a post-operative X-ray is considered a "never event" in healthcare—a serious, preventable medical error.

In medical imaging, an X-ray that includes sponges typically refers to the detection of a (gossypiboma or textileoma) following a surgical procedure . The Role of Radiopaque Markers

: These markers allow radiologists to quickly identify the presence and exact location of a sponge within a patient’s body cavity if the manual sponge count is incorrect. Radiographic Appearance

: On an X-ray, this marker appears as a distinct, high-density linear or "ribbon-like" shadow.