EFHSS Questions and Answers - Question Q00166

Hi! Everyone! I am Venugopal again!

There is a practice of all surgeons, especially endoscopic surgeons to keep their scopes, Tungsten Carbide/Titanium Dioxide Instruments etc. in an acrylic chamber where they allow a few tablets of Formalin to fume. There is no specific timing, concentration etc. They are kept after one use to the next use. Many of the Surgeons believe that the instruments are sterile if kept in these acrylic chambers.

Is there any recognised procedure like this? Or are there guidelines for this type of procedures? Even the ones who have studied abroad in reputed hospitals here follow this seemingly absurd procedure!!

Regards
Venugopal.K.G

Dear,

There are no recognised procedures or guidelines for the use of formalin tablets as sterilant. Simply because this is NOT a sterilization method. In the best case you could consider it as a disinfection with, even then, an unsure outcome - depending on relative humidity (RH) and concentration - (see question Q00158 and other low temperature sterilization related questions).
Sterilization with formaldehyde (LTSF) is tied to strict parameters: concentration, RH (extremely important), temperature and time. CEN/TC 102 at the moment is preparing a document about LTSF sterilizers: "Sterilizers for medical purposes - Low temperature and steam formaldehyde sterilizers - Requirements and testing".

If you use formalin tablets, you can't control neither concentration nor RH nor temperature. And what about the penetration in instruments with a lumen and eventual deposits on the instruments?
Anyway the result of the process is unpredictable and can't be guaranteed. If the RH is too low you don't even get a 3 log reduction of the initial population (ref.Hygiene Hospitaliere Pratique, Darbord)!!!
I advise you to end this practice as soon as possible and to look for more reliable and reproducible methods. i.e. steam sterilization of compatible instruments, sterilization with liquids i.e. glutaraldehyde, orthopthaladehyde (see ASP website), peracetic acid.

Success,
Wim Renders