Protein S Activity, Reflex

Test Code: TD_1464
CPT Code(s): 85306

$39

Test Details

Alternative Name(s)

N/A

Test Includes

Protein S Activity

Methodology

Immunoturbidimetric

Rejection Criteria

Room temperature samples
Refrigerated samples
Clotted samples
Samples submitted in inappropriate anticoagulant

Reference Range(s)

Age and gender specific normals.
Will reflex to Protein S Antigen free and Protein S Antigen Total when result is below reference range.
Additional charges will apply

Specimen Requirements

Preferred Specimen

Sodium Citrate Light Blue Top Tube

Minimum Volume

2 aliquots of 1 mL frozen plasma each

Sample Stability

4 hours room temperature
Unacceptable refrigerated
1 month frozen at -20 degrees C

Transport Temperature

Critical Frozen

Collection Instructions

1. This test requires 2 frozen plasma aliquots. Fill 2 light blue top tubes 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 tubes 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.
3. To obtain platelet-poor plasma, immediately centrifuge samples at 1500 RCFs for 15 minutes, then pipette the supernatant plasma and transfer to 2 plastic transport tubes.
4. Re-centrifuge plasma in the plastic transport tubes 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 divide all plasma evenly and transfer to 2 separate plastic transport tubes. Clearly label tubes as citrate plasma.
6. Immediately freeze the plasma at -20 degrees C or lower for transport.
7. When multiple tests are ordered, submit separate tubes 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.

Alternative Specimen

N/A