The use of the self-contained biological indicators significantly minimizes the chances of a “false positive” occurring. Generally, if a self-contained biological indicator is positive there is a good reason why the spores have survived the process.

Air pockets create the greatest problems in steam sterilizers that “appear to be working perfectly”. The EZTest unit should always be placed in the sterilizer lying on its side. This allows the air in the bottom of the plastic tube to easily flow out of the container and be replaced by saturated steam. If the EZTest is placed in the sterilizer in an upright position air can become trapped in the bottom of the plastic vial and prevent saturated steam from reaching the spores on the paper carrier in the bottom of the vial. If the EZTest unit is placed in the bottom of a container, such as a large flask, that is upright, then air can stay trapped in the bottom of the flask and prevent steam from reaching the EZTest biological indicator. If the EZTest unit is placed in the center of a densely packed fabric, load air can be trapped inside the fabric also insulating the biological indicator from saturated steam. Placement of the EZTest in a long coiled lumen device can also allow air pockets to protect the biological indicator from saturated steam.

Carefully review the placement of the biological indicator in the sterilizer and the load to see if trapped air could be a problem. A positive biological indicator is an indication of a serious problem because if the biological indicator survived, there is a good chance that the materials processed are not sterile either.