1. This test requires 2 frozen plasma aliquots. Fill 2 light blue top tubes as far as vacuum will allow and mix by gentle inversion five to six times. The exact ratio of 1 part sodium citrate to 9 parts blood must be maintained. Inadequate filling of the tubes will alter this ratio and may lead to inaccurate results.
2. Patients WHO have hematocrit values above 55% should have the anticoagulant adjusted to maintain the 1 to 9 ratio. For further instructions on the collection of platelet-poor plasma for patients with hematocrit value of >55%, please contact customer service.
3. To obtain platelet-poor plasma, immediately centrifuge samples at 1500 RCFs for 15 minutes, then pipette the supernatant plasma and transfer to 2 plastic transport tubes.
4. Re-centrifuge plasma in the plastic transport tubes at 1500 RCFs for 15 minutes to ensure that no red cells are present.
5. Pipette the top two-thirds of the supernatant plasma and transfer 2 mL plasma to each of 2 plastic transport tubes.
6. Immediately freeze the plasma at -20 degrees C or lower for transport.
7. When multiple tests are ordered, submit separate tubes for this test.
Patient prep: patients should discontinue oral anticoagulant therapy for at least 2 weeks prior to testing, upon the advice of their physician.