Lt blue Sodium citrate (NaCit)

1. Blood should be collected in a blue-top tube containing 3.2% buffered sodium citrate.
   1. Evacuated collection tubes must be filled to completion to ensure a proper blood to anticoagulant ratio.
2. The sample should be mixed immediately by gentle inversion at least six times to ensure adequate mixing of the anticoagulant with the blood.
3. A discard tube is not required prior to collection of coagulation samples, except when using a winged blood collection device (ie, "butterfly"), in which case a discard tube should be used.

If the patient's hematocrit exceeds 55%, the volume of citrate in the collection tube must be adjusted. Coag - Hematocrit anticoagulant adjustment

Platelet poor citrated plasma samples (PPP) should be obtained by double centrifugation.

1. Centrifuge for 10 minutes and carefully remove 2/3 of the plasma using a plastic transfer pipette, being careful not to disturb the cells.
2. Deliver to a plastic transport tube, cap, and recentrifuge for 10 minutes.
3. Use a second plastic pipette to remove the plasma, staying clear of the platelets at the bottom of the tube.
4. Transfer the plasma into a LabCorp frozen purple tube with screw cap.
5. Freeze immediately and maintain frozen until tested.

Screw-cap polypropylene frozen transport vial/tube - 4mL (LabCorp)

Frozen (strict)

• Gross hemolysis
• Clotted specimen
• Frozen specimen thawed in transit

Total and Free PS antigens: latex immunoassay

Free PS: EIA after C4b-BP complexed PS is precipitated out with polyethylene glycol

Total: In newborns, total PS levels are lower than in adults (12% to 60%). Levels gradually reach adult ranges by six months of age