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Laboratory Medicine

Test catalogue

Protein S Antigen, Free

Test Name

Protein S Antigen, Free

Blue Tube Specimen Type / Requirements

Container Type = Blue

Minimum Volume = 9:1 Ratio – Full Draw

Specimen Handling

Collection Instructions: Collect blood into blue top vacutainers which contain 3.2% buffered sodium citrate. NOTE: The ratio of blood to anticoagulant is 9 parts blood to 1 part anticoagulant, therefore the blue top vacutainer (citrate) must be filled AT LEAST ¾ in total volume. Must specify Heparin therapy. Haematology consult is REQUIRED for in-patient samples. Please call Special Coagulation at ext 5123 or the Haematologist on call

Write your initials, date and time of collection on the collection label.

Stability: Stable frozen at -20C for up to two weeks or -70C for up to six months

Transportation: Send sample to core lab as soon as posible. Specimens that cannot be tested within the suitable timeframe (within 2hrs of Collection) are to be double-spun and send frozen

Laboratory Staff Instructions: Centrifuge the blood sample at 4000 RPM (1500 G) for 15 minutes at room temperature (18-24˚C). Transfer the plasma fraction into a clean 10.0 mL plastic, conical tube. Re-centrifuge the plasma at 1500g for 5 minutes at room temperature (18 - 24˚C). Seperate and store plasma frozen at -70˚C, if testing cannot be performed within 2 hours

Sample Rejection Criteria: Clotted sample, Grossly hemolyzed samples, Unlabeled or Not Sufficient Quantity Samples will be rejected

Required Documentation

Regular HIS order or Haematology requisition required.

Turnaround Time (TAT)

7 days

Test Utilization

>7 Days

Reference Value

Male = 0.60 – 1.28 U/mL

Female = 0.50 – 1.22 U/mL

Test Code



Chromogenic Immunoassay

Testing Location

SMH-Special Coagulation

Other information