The importance of how samples are preserved prior to arriving at the laboratory is often underestimated. It is of paramount importance to preserve samples properly, otherwise they can break down and you’ll be forced to go back out and re-collect them – a waste of your time.
Key tips for tissue samples:
- Keep the tissue cool; it’s best to keep them at 2-8 degrees
Bacteria are present in ALL collected samples. The bacteria will grow and replicate if stored in warm environments. This will cause the bacteria that you’re looking for to be contaminated by unspecified bacteria. This can generate toxic products that might kill viruses or fungus you’re looking for.
- Keep the tissue samples separate from one another
As tissues get grouped together, bacteria from one can quickly overtake another. This is especially true if intestinal samples or faecal materials are included. You should use specially designed bio-hazard bags like the PathoSeal that can be properly sealed and prevent leakages.
Key tips for serum samples:
- Let the blood coagulate
This is best done by using the plain, red top tubes and leaving them at 37° for 12-24 hours. The red top on the tube is a universal symbol that the tube contains no anticoagulant; consequently, the blood will coagulate.
- After coagulation, remove the serum and put into a clean tube
If you don’t remove the serum, the red cells in the clot will slowly break down, releasing their haemoglobin into the serum. This will make many serology tests difficult to process accurately.
- Keep the clean tube with the sample in it cool until you can get it to a laboratory
- If it will be longer than a week before shipping, freeze the sample to prevent drops in antibody levels
- Keep fecal samples cool until they can be sent to a laboratory, but do not freeze them; attempt to keep them around 4°c.