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Sample Processing and Storage

Instructions for Sample Processing and Storage

After the whole blood samples have been collected, the serum or plasma should be separated from the cells as soon as possible (i.e. within 2 hours).  It is highly recommended that serum samples be sent for testing.

Serum

Once the whole blood samples are collected, quickly transfer them into tubes with tops or caps – this will prevent evaporation and aerosolization of infectious particles during centrifugation.  Allow the samples to clot at room temperature for 90 minutes for complete clot formation.  Do NOT allow the samples to clot at 4 degrees centigrade, as this will cause hemolysis.  After 90 minutes of clotting at room temperature and prior to centrifugation, run a wooden applicator stick along the interior wall of the tube to disrupt clot adhesion to the tube wall.  Centrifuge the samples at 2000 X g for 15 minutes at room temperature.  (To convert 2000 X g to rpm, refer to the operating manual for the particular centrifuge).

After centrifugation, remove the serum and place it into a polypropylene microcentrifuge tube or a 12 X 75 polypropylene tube.  Please do not store/ship samples in glass tubes.  Clearly label the tubes with the identifying information.  Identify the samples with numbers in a sequential fashion.  This may require you to generate a master key with your own identifiers cross referenced with the sequential numbers.  After the serum has been separated from the cells, the serum samples should be stored at -20 degrees centigrade in a non-frost free freezer until shipping.

Plasma

Once the whole blood samples are collected, quickly transfer them into tubes with anticoagulant and tops or caps – this will prevent evaporation and aerosolization of infectious particles during centrifugation.  Invert the tubes to mix the samples well with the anticoagulant.  Centrifuge the samples at 2000 X g for 15 minutes at room temperature. (To convert 2000 X g to rpm, refer to the operating manual for the particular centrifuge).

After centrifugation, remove the plasma and place it into a polypropylene microcentrifuge tube or a 12 X 75 polypropylene tube.  Be as careful as possible not to transfer the red cells along with the plasma.  Please do not store/ship samples in glass tubes.  Clearly label the tubes with the identifying information.  Identify the samples with numbers in a sequential fashion.  This may require you to generate a master key with your own identifiers cross referenced with the sequential numbers.  After the plasma has been separated from the cells, the plasma samples should be stored at -20 degrees centigrade in a non-frost free freezer until shipping.

Preparing Tissue Homogenates

Homogenize the tissue in PBS (without detergent or EDTA).  After using a mechanical homogenizer, sonicate the homogenate for 60 seconds, to ensure cell disruption.  Centrifuge the tissue homogenate to remove cell debris.

After centrifugation, remove the tissue homogenate supernatant and place it into a polypropylene microcentrifuge tube or a 12 X 75 polypropylene tube.  Please do not store/ship samples in glass tubes.  Clearly label the tubes with the identifying information.  Identify the samples with numbers in a sequential fashion.  This may require you to generate a master key with your own identifiers cross referenced with the sequential numbers.  After the tissue homogenate supernatant has been separated from the tissue debris, the tissue homogenate supernatant samples should be stored at -20 degrees centigrade in a non-frost free freezer until shipping.