What are swipes used for with the Wipe Test Plate? Posted on April 18, 2018 Swipe assays are routinely performed in laboratories and other facilities that use or handle radioactive materials. These assays, often referred to as smear or wipe tests, are performed to comply with radioactive material license requirements, assure laboratory safety, and provide information that proper handling procedures are being followed. Typically, swipes are performed to monitor for the presence of removable surface contamination from low energy beta-emitting radionuclides. Swipe assays are also used to detect the presence of alpha contamination. By using the Ranger wipe test plate and a swipe, you can perform a timed count and get a more accurate reading of your potential contamination.