Test Catalog



Alternative Names: PROS, 1779, I332
Includes: Protein S Activity, Protein S Activity
Sample Type: Plasma
Preferred Container: Sodium Citrate (Light Blue Top) Tube
Sample Volume: 1.0 mL
Handling Instructions: Platelet Poor Plasma. See special instructions.
Transport Temperature: Critical Frozen
Specimen Stability: Frozen: 1 month
Testing Frequency: Monday- Friday
Expected Turn Around Time: 4-7 days
Testing Facility: Ref Lab CPL
CPT Codes: 85306
Note: 1. Fill a light blue top tube 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 sample tube 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 CPL Austin customer service.
3. To obtain platelet-poor plasma, immediately centrifuge sample at 1500 RCFs for 15 minutes, then pipette the supernatant plasma and transfer to a plastic transport tube.
4. Re-centrifuge plasma in the plastic transport tube 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 to another plastic transport tube.
6. Immediately freeze the plasma at -20 degrees C or lower for transport. Critical frozen (CFZ).
7. When multiple tests are ordered, submit separate tube 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.