February 2021

Protecting Biopsy Samples from the Winter Freeze During Shipment

By Dr. Sasha Thomason

The subzero temperatures we experienced this past week caused many biopsy samples we received to freeze in-transit. Unfortunately, freezing causes biopsy samples to be undiagnostic in most instances.

When fixed tissues freeze, it causes ice crystals to form in the tissues and “crack” the tissues. The ice expands and pulls apart the tissues, then when they thaw, the gap in the tissue remains. This artifact makes it difficult to impossible for the anatomic pathologist to provide a diagnosis for your patient. To minimize this impact, there are shipping options you can use when submitting biopsy samples during times of extreme cold.

Normal artifact
Normal tissue appearance
Freeze artifact
Tissue with freeze artifact

Options for Shipping When Temps are Below Freezing :

  1. You can add one-part isopropyl alcohol to nine parts formalin in your biopsy containers. The addition of alcohol lowers the freezing point of the formalin. (However, adding too much alcohol will dry out the tissues and decrease diagnostic quality, so there is a limit to how much can be added.) The biopsy kits we provide our clients already have alcohol mixed into the formalin during the winter months. A sticker on the side of the formalin container will indicate that “isopropyl alcohol added to prevent freezing”, if it contains the 10% alcohol. If you would like to order these pre-filled formalin containers with 10% alcohol added, you can do so by contacting our Client Care team and requesting a “histo kit”.
  2. Add additional, substantial insulation (towels, newspaper, etc.) to the package, use a styrofoam container, and add hand warmers to the package to prevent freezing. Using Next-Day delivery to minimize the time the package spends in a cold truck, on a cold dock or in a cold warehouse will also help.
  3. Hold the sample in your clinic until temperatures return to above freezing levels and ship then.

Sasha Thomason, DVM is the Section Head for Accessioning at the Kansas State Veterinary Diagnostic Laboratory.

Next: Shipping Trich Samples in Cold Weather
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