FDA says exposure to cyanide gas possible with some workflows to test for COVID-19
The U.S. Food and Drug Administration (FDA) cautioned laboratory staff members about the risk of exposure to harmful cyanide gas when they use transport media containing guanidine thiocyanate or similar chemicals with testing platforms or laboratory processes that use bleach.
In a letter to labs posted on its website, the agency noted that cyanide gas is a by-product of a reaction between guanidine thiocyanate or similar chemicals and bleach (sodium hypochlorite).
As a result, the agency said these transport media should not be used with the Hologic Panther and Panther Fusion Systems because of a disinfecting step involving bleach that is specific to the testing platform.
Similarly, the agency said laboratories should not use cleaning agents containing bleach on testing platforms that use guanidine thiocyanate or similar chemicals—either in transport media or sample processing reagents.
These transport media also should not be used in laboratories that use bleach as part of their normal laboratory processes, the agency said, noting that many laboratories use bleach in their cleaning or decontamination processes in response to laboratory spills.
There are numerous transport media that contain guanidine thiocyanate or similar chemicals, such as guanidinium rhodanide, guanidinium thiocyanate, or guanidinium, according to the FDA. Some of these transport media include:
· PrimeStore molecular transport media (MTM) (LH-1-02 and LH-1-03)
· Zymo DNA/RNA Shield
· Spectrum Solutions Saliva Collection Device
The FDA also noted that other transport media may contain guanidine thiocyanate or other similar chemicals, and the ingredients in the transport media may not be listed on individual tubes.
The FDA said while it has received reports of these potentially hazardous interactions, there have been no injuries reported to the agency associated with exposure to cyanide gas as a result of using incompatible media with testing platforms.
In other recommendations, the FDA said labs should:
· Review the instructions from the testing-platform manufacturer about which transport media should be used.
· Do not separate transport media tubes from the manufacturer's labeling.
· If you can identify the contents of the tube through associated packaging or information from the distributor, place a label on a specimen collection tube that identifies the type of transport media inside. If you do not have a label, contact the manufacturer to obtain one.
· If you cannot identify the type of transport media in the specimen collection tubes or if you do not know if the transport media contains guanidine thiocyanate or similar chemicals as an ingredient, handle tubes as if they contain guanidine thiocyanate or similar chemicals.
