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Platelet Poor Plasma

Platelet Poor Plasma

Explanation: The accuracy of hemostasis (coagulation)  testing depends upon the quality of the specimen submitted. Hemostasis specimens must be properly collected, labeled, stored, packaged, and transported. Since platelets contain clotting factors which can activate the clotting cascade, most coagulation tests require submission of platelet poor plasma (PPP) for analysis.  Ideally, PPP should have a platelet count of less than 10 x 10E9 per liter (<10,000 /ul).

 

Specimens requiring Platelet Poor Plasma (PPP) must be collected and handled in the following manner:

Specimen Collection:

  1. Obtain venous blood by drawing a clearing tube prior to obtaining the specimen. Draw the specimen in a light blue top sodium citrate tube. Avoid stasis and contamination of the specimen by tissue thromboplastin. 
  2. Mix blood with anticoagulant (3.2% buffered sodium citrate) by gentle inversion. An exact ratio of 9 parts blood to 1 part coagulant should be maintained. 

Specimen Handling:

  • Specimens drawn at Regional Sites:
    • Prior to centrifugation, check specimen for clots with applicator sticks.
    • If transportation to MIB laboratory is to be delayed for more than 1 hour.
      1. Centrifuge tube to obtain PPP.
      2. Use a plastic transfer pipette to remove plasma (staying away from the buffy coat layer) and transfer top ⅔ of plasma to a plastic aliquot tube. 
      3. Centrifuge this aliquot tube at 1500 g for 10 minutes.
      4. Transfer top ¾ of plasma (do not disturb button at bottom of tube) into another plastic aliquot tube.
      5. Label this tube with patient identification and a PLASMA sticker .
      6. Freeze plasma immediately in -15°C to -20° C freezer until ready to transport. (may only be stored for up to 2 weeks at this temperature)
  • Specimens drawn at MIBH (IP's or OP Clinics):
    • Transport to laboratory as soon as possible.  Platelet poor plasma preparation will be performed by laboratory personnel.