The Thermo Scientific Pierce Silver Stain Kit is a rapid and ultrasensitive silver stain system for protein detection in polyacrylamide gels. The stain performs consistently and reliably for both first-time and experienced users for high, low or gradient percentage gels in single-dimension or 2-D format. The Pierce Silver Stain Kit provides consistency, high sensitivity, low background and a flexible protocol. Careful manufacturing procedures and thorough quality testing ensure that the kit yields excellent results with every use, independent of the polyacrylamide gel type or buffer system being used. Most proteins are easily detectable at low nanogram or subnanogram amounts, and background levels are very low (see Additional Information section at the end of these instructions). The protocol clearly indicates how both fixing and staining steps can be extended overnight without compromising performance, a feature that enhances convenience for ordinary workday schedules. Likewise, the default 30- minute staining step can be decreased to 5 minutes, enabling the staining procedure to be completed in less than 20 minutes after gel fixation.