• Store swabs in a refrigerator at no more than 46 degrees F.
• Avoid leaving swabs at room temperature for more than 20 minutes.
• ATP systems may need to conduct a “self-test” for about 60 seconds when first turned on. Avoid using the unit until it has finished performing this test.
• For flat surfaces, swab a 4-in. x 4-in. area, moving the swab from left to right and up and down.
• For irregular surfaces such as door handles, swab enough of an area to collect a good sample.
• Rotate the swab during use so all areas of the swab come into contact with the surface to be tested.
• After using the swab, place it in a tube, provided with most systems. Snap the top of the tube to release a liquid that protects the sample.
• Hold the tube vertically and shake it back and forth for about five seconds.
• Keeping the swab upright, insert it into the monitoring device for testing.
• Wait about 15 seconds.

This cleanroom tip was taken from “Avoiding the ‘Killer Defect’” by Robert Kravitz.