Preferred Specimen(s) One full 3.2% sodium citrate (light blue-top) tube
Instructions A completely filled tube is necessary because the correct ratio of blood to citrate is critical (9:1). Mix by gentle inversion 3-4 times. Do not uncap. Stable 2 days at room temperature. If the specimen will be delayed longer than 2 days, centrifuge the specimen for 15 minutes at 1500 RCF (relative centrifugal force). Using a plastic pipette, remove plasma, taking care to avoid the WBC/platelet (buffy) layer and place into a plastic screw-cap vial and freeze at – 20o C. Ship on dry ice.
Transport Container
Whole blood: 3.2% sodium citrate (light blue-top) tube
Plasma: Plastic screw-cap vial (frozen)
Transport Temperature Room temperature: (Light blue-top) tube (whole blood) Frozen: Plasma
Reject Criteria
- Gross hemolysis
- Improper blood to citrate ratio
- High hematocrit
- Improper blood collection
Methodology Clotting Method
Clinical Significance Screening test for abnormalities of coagulation factors that are involved in the extrinsic pathway. Also used to monitor effect of Coumadin® anticoagulants and study the patients with hereditary and acquired clotting disorders.