June 1 LOCS (CDC) Email

Subject: Lab Alert: Molecular Transport Media (MTM) and Cyanide Gas
Audience: Clinical Laboratory Professionals
Level: Laboratory Alert

PrimeStore MTM transport media contains guanidine thiocyanate, which produces a dangerous chemical reaction that releases cyanide gas when exposed to bleach (sodium hypochlorite). The PrimeStore MTM transport media being provided by state health departments is labeled at the bulk box level, but individual vials lack labels and therefore should be handled with caution. Do not use PrimeStore MTM with platforms that include a disinfecting step that uses bleach (e.g., Hologic Panther, Panther Fusion Systems).

Other MTM may contain guanidine thiocyanate, and ingredients in MTM may not be listed on individual vials. If samples are received in unfamiliar transport media, laboratories should make sure the media does not contain guanidine thiocyanate before processing the samples in a system that uses bleach.

Online resources:

• Clinical Laboratory COVID-19 Response Weekly Calls
• CDC's Laboratory Outreach Communication System (LOCS)
• COVID-19 Information for Laboratories
• CDC COVID-19 website
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