Test Directory

This test is used for confirmation and characterization of protein S (PS) congenital deficiency.

Specimen Type: Citrated Platelet-Poor Plasma

Collection Container: Light Blue Top (Sodium Citrate)

Desired Specimen Volume: 1 mL

1. Collect specimen in 2 light blue top (sodium citrate) tubes via venipuncture.
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 unless the sample is collected using a winged (butterfly) collection system. With a winged blood collection set a discard tube should be drawn first to account for the dead space of the tubing and prevent under-filling of the evacuated tube.
4.  When noncitrate tubes are collected for other tests, collect sterile and nonadditive (red-top) tubes prior to citrate (blue-top) tubes. Any tube containing an alternative anticoagulant should be collected after the blue-top tube. Gel-barrier tubes and serum tubes with clot initiators should also be collected after the citrate tubes.

Platelet-Poor Plasma Processing Instructions

1. Perform platelet poor plasma processing procedure
2. Transfer 1 mL of platelet-poor plasma to a LabCorp PP transpak frozen purple tube.

Avoid warfarin (Coumadin®) therapy for two weeks and heparin therapy for two days prior to the test. Do not draw from an arm with a heparin lock or heparinized catheter.

Transport to the laboratory frozen. 

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

 See patient report.

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