Protein S, free Ag w/ reflex to activity

Alphabetical Test listing

Protein S, free Ag w/ reflex to activity-5750

  
Protein S, free Ag w/ reflex to activity
  
5750
  
LAB5750
  
PRS
  
Protein S, functional & free
Protein S, activity
  
  • Protein S, free
  • Abnormals will reflex to a Protein S, activity at an additional charge
  

Interferences

Protein S, free: Warfarin (Coumadin)

Protein S, activity:

Clot based assay results may be falsely elevated due to interferences from several anticoagulants (High level Heparin, direct oral anticoagulants, direct thrombin inhibitors). Warfarin will lead to falsely decreased results.

  

Warfarin (Coumadin) therapy should be discontinued two weeks prior and heparin therapy two days prior to sample collection.

  
Sodium citrate (Na cit) plasma
  

 Lt blue Sodium citrate (Na Cit) - 2.7mL

If the patient has a hematocrit >55, a specially prepared Lt blue Sodium citrate (NaCit) tube must be used in place of the standard Lt blue Sodium citrate (NaCit) tube.

Hematocrit-Anticoagulant adjustments

  
1.5 mL
  
  • Do not draw from an arm with a heparin lock or heparinized catheter
  • Do not over or under fill tube as the ratio of anticoagulant to whole blood is critical

Coag – tube fill guidelines

  • Mix by gentle inversion 3 - 4 times
  
  

Microcentrifuge vial/tube in a Snap cap conical vial/tube and cap (Beaker sites)

     

   

Coagulation specimen transport vial/tube  (all other sites)

             

  

Frozen (strict)

Refrigerated - NO

  
  • Greiner tubes are not acceptable
  • Improper labeling (unlabeled or mislabeled)
  • Improper anticoagulant
  • Improperly filled tube
  • Hemolysis
  • Clotted specimen
  • Delay in transport
  • Improper storage/transport temperature
  • Patient on heparin > 1.0 IU/mL
  
AHL - Coagulation/Special Coagulation: V
  
Varies: 1 - 2 times/wk
Available STAT
  
3 - 5 days
  

Protein S, free – Immuno-turbidometric

Protein S, activity - Clotting assay

  

Protein S, free (Antigenic):

Female: 50-134%

Male: 70-148%

 

Protein S, activity:

Female: 50 - 120%

Male: 60 - 120%

 

  

Guidance for the evaluation and treatment of hereditary and acquired thrombophilia

Types of Heterozygous Protein S deficiency

 

Protein S, free Ag

Protein S, total

Protein S, activity

Type I

Decreased

Decreased

Decreased

Type II

Normal

Normal

Decreased

Type III

Decreased

Normal

Decreased

 

The three subtypes of heritable protein S deficiencies include both qualitative and quantitative defects. Type I is a quantitative defect resulting in decreased plasma antigen levels of both free and total protein S antigen. Type II is a qualitative defect with decreased protein S activity and normal levels of free and total protein S antigen. Type III is characterized by decreased free protein S antigen and protein S activity with normal levels of total protein S antigen. Type I and III protein S deficiency are much more common than type II (dysfunctional) protein S deficiency.

Acquired free protein S deficiency may be seen in certain inflammatory conditions and will most often have decreased levels of free protein S antigen and protein S activity, but normal to elevated total protein S antigen. The hemostatic implications for patients with acquired protein S deficiency are of unclear clinical significance.

Reference:

Quality in Laboratory Hemostasis and Thrombosis. Kitchen, Steve, Olson, John D., and Preston, F. Eric. 2009 Blackwell Publishing Ltd, Sussex, UK. pg. 152.

  
85306 - Protein S, free antigenic
85306 - Protein S, activity (if appropriate)
  
11/30/2001
  
02/02/2021
  
02/02/2021