Clinical Conditions
Bleeding Disorder Assays

Hemorrhage is defined as bleeding that is inappropriately severe, occurs from two or more sites, or cannot be stopped without a specific intervention.

Hemorrhage is often associated with a coagulopathy, which may be detected through the following primary assays:

• Prothrombin time (PT) with INR
• Partial thromboplastin time (PTT)
• Fibrinogen functional assay
• Thrombin time

Refer to Management of Bleeding for detailed information.

In the event of a prolonged PT or PTT, the following mixing studies may be ordered to distinguish between a coagulation factor deficiency and an acquired inhibitor:

• PT mixing study
• PTT mixing study 

Individual coagulation factor assays may be ordered when a coagulation factor deficiency is indicated by the results of the above studies. Contact the UAB Coagulation Service for consultation and assistance in selecting factor assays. The following are available:

• Factor II assay
• Factor V assay
  The name of the "factor V assay" is regrettably similar
  to the "factor V Leiden mutation assay."
  Please select "confusing test names" for more information.
• Factor VII assay
• Factor VIII assay
• Factor IX assay
• Factor X assay
  The name of the "factor X assay" is regrettably similar
  to the "heparin anti-Xa chromogenic assay."
  Please select "confusing test names" for more information.
• Factor XI assay

 Von Willebrand disease (vWD) profile:

• Von Willebrand factor (vWF) antigen
• VWF activity (ristocetin cofactor)
• Factor VIII activity

 Follow-up vWD profile when profile results indicate a possible type 2 von Willebrand disease:

• VWF multimers
• Ristocetin response curve

 The following specialized procedures are available from the UAB Coagulation Service. Contact us for consultation:

• Factor VIII inhibitor titer
• Factor IX inhibitor titer
• Factor XIII assay
• Platelet aggregation assay
• Reptilase time
• Euglobulin clot lysis time

Laboratory Assays Menu: