A biological sterilization indicator includes a housing having a first enclosure and a second enclosure, an ampule containing a liquid growth medium, and an insert disposed at least partially in the first enclosure. A portion of the ampule may be disposed inside the first enclosure. The insert may have a platform including a top surface, an abutment surface, and a side surface, as well as a first void disposed in the platform and configured to allow passage of a first volume of the liquid growth medium into the second enclosure and a second void disposed through at least a portion of the side surface and configured to allow passage of a second volume of the liquid growth medium into the second enclosure.