What blood tests are used to diagnose and manage bleeding disorders?

From the Guidelines

The most important blood tests used to diagnose and manage bleeding disorders include a complete blood count (CBC), prothrombin time (PT), activated partial thromboplastin time (aPTT), and specific tests for von Willebrand disease, such as von Willebrand factor antigen and activity tests. These tests form the initial screening panel for bleeding disorders, as recommended by the 2008 NHLBI/NIH guidelines 1. The CBC evaluates platelet count and can identify thrombocytopenia, while PT and aPTT measure the function of clotting factors in the extrinsic and intrinsic coagulation pathways, respectively. More specific tests, such as mixing studies, specific factor assays, and platelet function tests, can help differentiate between factor deficiencies and inhibitors, and identify specific bleeding disorders, such as hemophilia A or B, or von Willebrand disease. Genetic testing can also identify inherited bleeding disorders, allowing for targeted treatment approaches and monitoring of therapy effectiveness. It's worth noting that some tests, such as the PFA-100, are not recommended due to insufficient specificity/sensitivity 1. In cases where bleeding disorders are suspected, a thorough physical examination and medical history are also essential in guiding the selection of blood tests and interpreting the results, as emphasized in the evaluation of cerebral venous thrombosis 1 and the assessment of bleeding disorders in children 1. Key points to consider when diagnosing and managing bleeding disorders include:

• Initial screening tests: CBC, PT, aPTT
• Specific tests for von Willebrand disease: von Willebrand factor antigen and activity tests
• More specific tests: mixing studies, specific factor assays, platelet function tests
• Genetic testing for inherited bleeding disorders
• Interpretation of test results in the context of medical history and physical examination.

From the FDA Drug Label

Desmopressin Acetate Injection is a vasopressin analog used for: Hemophilia A- for patients with factor VIII coagulant activity levels greater than 5% to maintain hemostasis during surgical procedures and postoperatively or reduce bleeding with episodes of spontaneous or traumatic injuries such as hemarthroses, intramuscular hematomas, or mucosal bleeding. von Willebrand's disease (Type I) - for patients with mild to moderate disease with factor VIII levels greater than 5% to maintain hemostasis during surgical procedures or traumatic injuries such as hemarthroses, intramuscular hematomas, or mucosal bleeding.

The blood tests used to diagnose and manage bleeding disorders, specifically Hemophilia A and von Willebrand's disease (Type I), include:

• Factor VIII coagulant activity levels to determine the severity of the disease and to monitor the effectiveness of treatment.
• Factor VIII antigen levels to diagnose and manage von Willebrand's disease. These tests are crucial in determining the appropriate dosage of desmopressin acetate and in monitoring the patient's response to treatment 2.

From the Research

Blood Tests for Bleeding Disorders

The following blood tests are used to diagnose and manage bleeding disorders:

• Complete blood cell count (CBC) to evaluate overall blood cell production 3, 4, 5
• Platelet count to assess platelet production and function 3, 6, 4, 5
• Prothrombin time (PT) to evaluate the extrinsic coagulation pathway 3, 6, 4, 5
• Activated partial thromboplastin time (aPTT) to evaluate the intrinsic coagulation pathway 3, 6, 4, 5
• Thrombin time (TT) to assess fibrinogen function and the presence of heparin or fibrin degradation products 6
• Von Willebrand factor antigen and activity assays to diagnose von Willebrand disease 3
• Factor VIII and IX assays to diagnose hemophilia A and B 3, 7
• Mixing studies to evaluate the presence of coagulation factor inhibitors 5
• Global hemostasis assays, such as thrombin generation and thromboelastography, to assess overall coagulation function 7

Specialized Tests

Additional specialized tests may be ordered to further evaluate bleeding disorders, including:

• Platelet Function Analyzer-100 to assess platelet function 4
• Inhibitor assays to detect the presence of coagulation factor inhibitors 4
• Multimeric analysis of von Willebrand factor to diagnose von Willebrand disease subtypes 3
• Bleeding assessment tools, such as the International Society on Thrombosis and Hemostasis bleeding assessment tool, to standardize the evaluation of bleeding symptoms 5

Interpretation of Test Results

The interpretation of blood test results requires consideration of the patient's clinical history, physical examination findings, and medication use. Abnormal test results may indicate a specific bleeding disorder, such as von Willebrand disease or hemophilia, and guide further evaluation and treatment 3, 6, 4, 5.