Reveal the hidden areas of instruments with the TOSI® washer test, the easy-to-use blood soil device that directly correlates to the cleaning challenge of surgical instruments. TOSI® is the first device to provide a consistent, repeatable, and reliable method for evaluating the cleaning effectiveness of the automated instrument washer. This is possible because the blood soil is manufactured to exacting specifications each time. When metered on to the stainless-steel plate, the TOSI® is completely analogous to a stainless-steel instrument soiled with dried blood. Placed in the see-through plastic holder, the challenge is identical to the areas of instruments typically hidden from view (i.e., box locks). The routine use of this test will help ensure that your instrument washer is performing at a consistent level, enhancing the routine visual inspection of instruments. TOSI® complies with new AAMI and AORN Guidelines as well as ASTM Guide D7225.