Verify Cronos is manufactured by Steris Corporation of Ohio, US.

Considered to be the first biological test, the SCBI can give results in just two hours. It is used in reprocessing, a multistep process to clean and disinfect or sterilize reusable medical devices, so that they can be used safely for more than one patient.

FDA Devices and Radiological Health Center Device Evaluation Office director Christy Foreman said this is an innovative use of recombinant DNA technology in biological indicator tests.

"By providing faster confirmation of sterilization, this innovation may help healthcare facilities provide their medical staff with a faster turnaround of their sterilized reusable devices," Foreman added.

One way of sterilizing the reusable devices such as surgical instruments and endoscopes is through steam. For this method, medical devices are put into a chamber and then sealed and filled with steam.

In order to destroy the micro-organisms that may be present on the reusable devices, certain conditions are maintained throughtout the process such as temperature, exposure time and chamber pressure.

The Verify Cronos SCBI consists of a vial, which contains dried spores from the heat-resistant bacteria Geobacillus stearothermophilus.

Before the commencement of the sterilization cycle, the vial is placed inside the sterilization chamber along with the sterilization load by a reprocessing technician.

Following the completion of the sterilization cycle, the spores are incubated in recovery medium, a liquid which provides an ideal environment for growth of any surviving bacteria, and then spore growth is monitored.

In case, the bacteria grows, it means the failure of the sterilization load.

The Verify Cronos SCBI test uses a genetically-engineered strain Geobacillus stearothermophilus that produces an enzyme that fluoresces in reaction with the recovery medium if test micro-organisms are present even after the process of sterilization.

Genetically-engineered geobacillus stearothermophilus that survive a sterilization cycle will start growing and producing the enzyme within two hours, giving technicians faster results than the usual process with a natural bacterial strain, which gives results in 24 hours.