name and number the different clotting factors involved in clotting of blood?

There are 13 blood clotting proteins (coagulation factor) found in the blood. They are designated by Roman Numerals I through XIII. When a blood vessel is damaged, these clotting factors are switched on in a certain order (Blood Clotting Cascade) [link to coagulation page] and work to form a clot. Specifically, these 13 factors normally combine to a clot.

If one factor is missing or present at low levels, this causes hemophilia and other blood clotting problems and a proper clot will not form.

The two most common factor deficiencies are: factor 8 (or factor VIII) deficiency and factor 9 (or factor IX) deficiency. The most common, affecting 80% of the hemophilia population - those with hemophilia A - is factor VIII. When these blood clotting proteins aren't present is not easily stopped.

This factor is so important to the treatment of hemophilia, that instead of saying they have "hemophilia A or B," most people say they are "Factor VIII" or "Factor IX" to identify their condition.