If there is a threat, a red box will appear on the outline at the location of the object. If there is no threat, an OK will appear on the screen without an outline. It will also allow the passengers to see what the TSA agents see when they step through the scanner.

In 2026, a red box appearing on a TSA full-body scanner (the Advanced Imaging Technology or AIT) indicates a "potential threat or anomaly" that requires a physical "pat-down" of that specific area. The scanner uses millimetric waves to detect objects under your clothing; if it identifies something with a different density or shape than the human body—such as a forgotten wallet, a thick belt buckle, or even a wad of tissues—it will highlight that location on a "generic avatar" with a red box. It does not necessarily mean you are carrying something illegal; it simply means the software cannot "clear" that specific body part automatically. In 2026, the updated TSA software is more precise, but "false alarms" still occur from heavy sequins on clothing, medical devices like insulin pumps, or even excess sweat on the skin. If you see a red box on the screen as you exit the machine, the officer will simply perform a targeted inspection of that area to ensure it is clear before allowing you to proceed.