Protein S Assay

From Anvita Health Wiki

Contents 1 Reference-interval 2 Increases 3 Decreases 4 Methods 5 Specimen 6 More General Terms 7 Additional Terms 8 References

Reference-interval

• total protein S:

• 70-140% of normal reference activity
• 0.67-1.25 U/mL
• 21-42 ug/mL

• free protein S (active form)

• 60-120% of normal reference activity
• 0.23-0.49 U/mL

Increases

• pharmaceutical agents:

• chemical interferences

• heparin, warfarin

• clinical disorders

Decreases

• pharmaceutical agents

• in vivo effects

• oral contraceptives, L-asparaginase

• clinical disorders: hypercoagulability

• congenital Protein S deficiency

• low functional & antigenic levels
• low functional & normal antigenic levels

• acquired Protein S deficiency

• hepatic disorders
• inflammatory syndromes

• increases in C4-binding protein may result in increased binding of protein S & decreased levels of free (active) protein S

Methods

• functional* clotting assay based on anticoagulant activity
• rocket immunoelectrophoresis
• enzyme-linked immunosorbant assays ( ELISA)
• microlatex particle mediated

• * NOT useful if patient is anticoagulated

Specimen

• plasma ( citrate)
• stable at room temperature for 8 hours
• stable at -20 degrees C for 1 month

More General Terms

• clinical hematology test

Additional Terms

• free protein S in plasma
• protein S deficiency
• protein-S

References

1. Medical Knowledge Self Assessment Program (MKSAP) 11, American College of Physicians, Philadelphia 1998
2. Clinical Guide to Laboratory Tests, 3rd ed. Teitz ed., W.B. Saunders, 1995

protein S activity in plasma (protein S assay)