Bowie-Dick test

A daily test of air removal and steam penetration in pre-vacuum steam sterilisers. A standard test pack with an indicator sheet is processed in an empty chamber, usually first thing in the morning. A uniform colour change on the sheet shows that air was removed and steam reached the centre of the pack. A lighter patch in the centre indicates residual air, a leak or poor steam quality, and the steriliser must not be used until the problem is fixed.