Our Partners











Diagnosis of inherited bleeding disorders in women

What routine screening tests are used?

The three most common screening tests are:

  • bleeding time (to find out how long it takes for a simple cut to stop bleeding)
  • PT (prothrombin time)
  • APTT (partial thromboplastin time).

Are these routine screening tests a good way to diagnose bleeding disorders?

No, they are not. These tests will often give normal results in women who have bleeding disorders. For example, in von Willebrand disease:

  • the prothrombin time is always normal
  • the partial thromboplastin time is almost always normal and
  • the bleeding time is often normal.


The prothrombin time will be prolonged only with factor I, II, V, VII and X deficiencies.

The partial thromboplastin time will be prolonged only with factor I, II, V, VIII, IX, X, XI and XII deficiencies.

What tests are reliable in diagnosing bleeding disorders?

For von Willebrand disease, these tests permit an accurate diagnosis:

Bleeding time This measures the length of time it takes for a simple cut to stop bleeding.
Factor VIII:C This measures the amount of Factor VIII clotting activity.
VWF: antigenThis measures the amount of Von Willebrand Factor.
Ristocetin cofactor activityThis measures how well the VWF works
VWF multimersThis measures the structure of the VWF.
Platelet function testsThese measure how well the platelets work.


For platelet function disorders, these tests permit an accurate diagnosis.

Bleeding time This measures the length of time it takes for a simple cut to stop bleeding.
Platelet aggregation studies These measure if there are abnormalities in the way platelets clump together.
Von Willebrand Factor studiesThese find out if the Von Willebrand Factor protein is working normally and rule out this similar disorder as the cause of the bleeding.
Specialized testsThese determine the exact type of platelet function disorder.


For hemophilia A and B, these tests permit an accurate diagnosis

Factor VIII assayThis measures the amount of Factor VIII activity in the blood.
VWF: antigenThis measures the amount of Von Willebrand Factor in the blood so as to rule out VWD as the cause of the bleeding in Hemophilia A.
Factor IX assayThis measures the amount of Factor IX activity in the blood.
Genetic studiesThese tests determine the exact genetic mutation and make it easier to provide prenatal diagnosis.


Because the other clotting factor deficiencies are so rare, tests are first done to rule out von Willebrand disease, platelet function disorders, and hemophilia A and B as the cause of bleeding. If one of the rare factor deficiencies is suspected, a laboratory assay is done to measure the level of the specific clotting factor.

Where are these tests done?

These tests are done in a lab which specializes in bleeding disorders. Most hemophilia / bleeding disorder clinics offer this service.

It is extremely important for a woman who suspects she has a bleeding disorder to go to a hemophilia / bleeding disorder clinic for testing. People at such a clinic know that tests often need to be repeated to get a correct diagnosis. This is because test results can be affected by:

  • normal hormonal changes that happen during a woman's monthly cycle
  • recent use of aspirin or other pain-killers
  • birth control pills, hormone therapy, pregnancy, breast feeding, or recent child birth
  • strenuous exercise, stress or crying just before having blood drawn
  • variation in the lab technologist's technique
  • blood type (Women with blood type O have naturally lower levels of von Willebrand factor and factor VIII than women with blood types A, B or AB.)


Because of these testing difficulties, many women have been told they have no bleeding disorder. In fact, they do.