Protein C and protein S are proteins that help regulate blood clot formation. They work together to inactivate factors V and VIII, slowing down clot formation. Deficiencies in protein C or protein S can lead to excessive clotting. There are inherited and acquired causes of low levels or abnormal function of these proteins. Inherited causes include insufficient production or abnormal function, while acquired causes include liver disease, vitamin K deficiency, and certain medical conditions or treatments.

1. PROTEIN C AND PROTEIN S
SURAMYA BABU

2.  Protein C and protein S are two proteins in the blood that help regulate blood clot
formation
 Often these two test are performed together as part of investigation of a possible
excessive clotting disorder.
 The test measure the amount of each protein ( antigen tests) and evaluate
whether they are performing their proper functions

3.  Protein S act as principle cofactor to protein C
 They work together to help regulate and control blood clot formation by
inactivating coagulation factors (factor V and factor VIII) that required to
generate and form blood clots.
 This has a net effect on slowing down clot formation . therefor, if there is not
enough protein C or protein S or they are not functioning normally, clot formation
can go unchecked , possibly leading to excessive clotting . These conditions can
range from mild to severe,

4. There are two types of inherited protein C deficiencies
 TYPE I : due to insufficient quantity
 TYPE II : due to abnormal function (it is less common than type I)

5. Protein S exists in two forms in blood
free and bound to another protein, but only the free protein S is available to be a
cofactor for protein C.
 3 types of inherited protein S deficiencies:
 TYPE I : due t insufficient quantity
 TYPE II : due to abnormal function
 TYPE III : due to decreased free protein S levels , though total protein S levels are
normal

6.  Normal activity and level of protein C and protein S usually indicate adequate
clotting regulation
 Low protein C or protein S level or activity indicates blood clotting is not
sufficiently regulated and there is an increased risk of developing a clot that
blocks the flow of blood in the veins

7. Acquired deficiencies
 Both proteins are produced in liver and depend on Vitamin K. Therefore, low levels may be due to ;
 Liver disease
 Vitamin K deficiency
 Warfarin anticoagulant therapy (a vitamin K antagonist )
 DIC
 Infections
 Inflammmation
 Kidney disease
 Chemotherapy
 HIV
 Pregnancy

8. Inherited deficiencies
 Decreased production of protein C or protein S
 Abnormal protein C or S that cannot function normally
 Abnormal protein S that is cleared more rapidly by the body ( type 3 deficiency)