It’s that time of year again when we need to start thinking about preventing samples from freezing. Specimens such as EDTA blood are rendered useless when frozen. Formalin will also freeze, which creates artifacts in fixed tissue. It can be difficult to protect samples shipped during the winter from severe cold. Even 10% neutral-buffered formalin will freeze in harsh winter weather conditions. To prevent formalin freezing, add 1 mL of ethanol per 10 mL of formalin. Avoid shipping temperature-sensitive samples on Fridays as the package may sit in an unheated truck or warehouse over the weekend.

Samples that should not be frozen should be shipped inside insulated containers with minimal cold packs. Use of room temperature cold packs will help prevent temperatures from dipping too low. If you have any concerns about the best way to ship critical samples, please contact the AHL at ahlinfo@uoguelph.ca