Texas Medical Assistant Certification Practice Test

Which statement about the autoclave process is correct?

1. It only uses dry heat to sterilize instruments.

2. It can destroy microorganisms even in cold temperatures.

3. Steam simultaneously heats and wets the items being autoclaved.

4. Only steam under pressure is effective.

The correct answer is: Steam simultaneously heats and wets the items being autoclaved.

The autoclave process effectively uses steam under pressure to achieve sterilization. When steam is introduced into the chamber, it not only heats but also saturates the surfaces of the items being sterilized. This combination of high temperature and moisture is critical for denaturing proteins in microorganisms, leading to their destruction. In autoclaves, steam must be at a certain temperature, typically around 121 degrees Celsius (250 degrees Fahrenheit) at a pressure of about 15 psi, to ensure that all microorganisms, including resistant spores, are effectively killed. The ability of the steam to penetrate and wet surfaces is crucial, as many materials require moisture to facilitate the heat transfer necessary for sterilization. The other statements present inaccuracies about how autoclaves function. An autoclave does not use only dry heat nor does it operate effectively in cold temperatures, as heat and moisture are necessary for effective sterilization. Also, while steam under pressure is indeed essential for the process, stating that "only steam under pressure is effective" doesn't capture all the dynamics involved, as the combination of heat and moisture is what truly enables effective sterilization.