Tissue Sampling Unit (TSU) - Preferred Method (Acceptable for twins) 1.) Ensure the tissue applicator is loaded with an unused tissue punch (red plunger should be visible). Order Online. 2.) Slide gun over the ear, and position the cutter approximately 1 inch from the edge of the ear, taking care to avoid any obvious veins and ridges. 3.) Squeeze handles together to take a sample and then release to free the ear. Try to do this in one swift, fluid, motion. 4.) Remove the punch from the device and check that sampling has been successful. If not, discard the sample and re-sample with a new punch. 5.) Remove the used cutter from the applicator by pulling the handles apart. This will loosen the cutter. Discard safely as cutter is very sharp. 6.) Record animal id (tattoo, tag, etc.) and reference barcode. Submission Instructions for TSUs Once the tissue sample has been successfully extracted, care should be taken to store the sample at room temperature and away from sunlight for up to a year. We recommend freezing the sample after a year, for long term storage.