Some specimens must be kept refrigerated following collection to avoid changes that will affect the test results. Laboratory refrigerators are kept at 4°C, with an acceptable range of 2-8°C. Refrigerated specimens must be maintained between 2-8º C during transportation. Examples of specimens that need to be kept refrigerated include:
- Albumin (ALB)
- Alkaline phosphatase (ALP)
- Alanine amino transferase (ALT)
- Aspartate amino transferase (AST)
- Ammonia (AMM)
- Arterial blood gases (ABG)
- Autoimmune antibody testing
- Certain viral tests
Some laboratories may require specimens for coagulation testing to be cooled.
Methods for transporting specimens needing to be refrigerated include:
- Plastic cooling blocks that hold blood collection tubes.
- Plastic cups with a slurry of wet ice and water. Tubes or cups must never be inserted into a cup of ice as this may result in super cooling and freezing at the tube or cup surface invalidating the test results.
- Frozen gel packs.
- Insulated coolers that must have a tight-fitting lid and maintain refrigerator temperature.