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Preparation of Platelet Poor Plasma for Special Coagulation Testing


Slide 20

October 2008

The processing risk factors for clotted specimens are as follows:

  • Centrifugation recommendations for coagulation specimens must be followed to insure that the plasma platelet levels are kept to a minimum, less then 10,000 per mcL.
  • Higher cell counts in licenses of those cells after a subsequent freeze cycle may cause the sample to clot.
  • Recommended speed is 1500 x G; recommended time of spin is 15 minutes. If the speed is too low, timed to short or the centrifuge is unbalanced there may be cellar contamination and the potential for clots.
  • Always use a plastic pipette for removing plasma.
  • Never pour off plasma directly from tube.
  • Excessive cellar contamination and the potential will be caused for pouring off plasma, rough handling, and pipetting into the cellular layer.
  • Specimens found with clot either before or after centrifugation must be rejected; the clotting cascade has started. The specimen will continue to form clots and test results would be potentially misleading.

Not performing the second spin will also leave too many cells remaining in the specimen and therefore will also be prone to clotting.



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