Factor VIII (FVIII) functions as
a co-factor in the blood coagulation cascade for the proteolytic activation of factor X by factor IXa
What is blood factor VIII?
Factor VIII (antihemophilic factor) is
the protein that is deficient or defective in patients with classical hemophilia and Von Willebrand syndrome
. Factor VIII in plasma is thought to be associated in a complex with the highest molecular weight multimers of another glycoprotein, Von Willebrand protein.
What Is factor VIII and what is its role in blood-clotting?
Factor VIII (FVIII) is
an essential blood-clotting protein
, also known as anti-hemophilic factor (AHF). In humans, factor VIII is encoded by the F8 gene. Defects in this gene result in hemophilia A, a recessive X-linked coagulation disorder.
How do you activate factor VIII?
Factor VIII is proteolytically activated by
thrombin or factor Xa
, and this process results in cleavages at sites within both the factor VIII heavy and light chains (Fig. 2). Thrombin attacks three bonds in factor VIII whereas factor Xa cleaves at these sites plus two additional ones.
What is Factor 9 in the blood?
Factor IX is
a protein that helps your blood clot
. If you are lacking this protein, you may have a bleeding disorder called hemophilia B. Hemophilia B is found mostly in males. When people with hemophilia get cut or injured, bleeding is hard to stop because their blood does not have normal clotting substances.
What is a normal factor VIII level?
Test results are usually reported as a percentage of a “normal” result of 100%. Normal ranges for factor VIII levels are
50% to 150%
. If your factor VIII activity level is less than 50%, you may have hemophilia A, but how severe your risk of bleeding is depends on what percentage you have.
Is Factor 8 a blood clotting disorder?
Hemophilia
is a disease that prevents blood from clotting properly. A clot helps stop bleeding after a cut or injury. In factor VIII deficiency (hemophilia A), the body doesn’t make enough factor VIII (factor 8), one of the substances the body needs to form a clot.
What causes high factor VIII?
Sustained rises in factor VIII are seen during pregnancy, surgery, chronic inflammation, malignancy,
liver disease
, hyperthyroidism, intravascular hemolysis, and renal disease. In most conditions, there is a concordant increase of factor VIII and vWF:Ag levels.
Is Factor 8 a blood product?
Until 1992, all factor replacement products were made from human plasma. In 1992, the U.S. Food and Drug Administration (FDA) approved recombinant factor VIII (8) concentrate, which
does not come from
human plasma.
Is Factor 8 genetic?
Hemophilia A
, also called factor VIII (8) deficiency or classic hemophilia, is a genetic disorder caused by missing or defective factor VIII (FVIII), a clotting protein. Although it is passed down from parents to children, about 1/3 of cases found have no previous family history.
How is factor VIII deficiency treated?
Desmopressin
raises the levels of factor VIII in the blood, and you take it through an IV or as a nasal spray. Drugs known as antifibrinolytics, such as aminocaproic acid and tranexamic acid, can also help if you have a mild form of the disorder.
What is factor 7 used for?
Factor VII is a protein produced in the liver that plays an important role in
helping your blood to clot
. It’s one of about 20 clotting factors involved in the complex process of blood clotting. To understand factor VII deficiency, it helps to understand the role factor VII plays in normal blood clotting.
What is Factor 9 called?
Factor IX (
or Christmas factor
) (EC 3.4. 21.22) is one of the serine proteases of the coagulation system; it belongs to peptidase family S1. Deficiency of this protein causes haemophilia B.
What is a normal factor 9 level?
Normal plasma levels of factor IX are
50 to 150 units/dl
. Patients with levels less than 1 unit/dl have severe disease, those with levels of 1 to 5 units/dl moderate disease, and those with levels greater than 5 units/dl mild disease. The half-life of factor IX is approximately 18 to 24 hours.
What is factor 10 called?
COAGULATION CASCADE | Factor X
Factor X (fX), also called
Stuart factor
, is a vitamin-K dependent serine protease zymogen that is activated in the first common step of the intrinsic and extrinsic pathways of blood coagulation.
What is a normal factor 7 level?
The reference range for factor VII is
65-140% of normal
.
