Some specimens will be labeled “frozen” and must be kept frozen immediately following collection, during transport, and must be placed into a freezer in the testing laboratory. Laboratory freezers are kept at a temperature of 0°C to -23°C.
Examples of frozen specimens can include:
- Fecal specimens for viral testing
- Fertility specimens
- Pleural pneumonia specimens
- Tissue specimens
- Viral specimens
Specimens that need to be kept frozen during the transportation process can be placed in heavy cardboard cartons with dry ice or insulated coolers with tight-fitting lids and freezer blocks. Specimens must not come into direct contact with dry ice or frozen blocks to avoid “spot freezing.” (It's important to note that if using dry ice to maintain frozen specimens, container lids should not be tight-fitting. This will be discussed later in this course.)