What are the lab orders for non-traumatic hemarthrosis (hemorrhosis into a joint)?

From the Guidelines

For non-traumatic hemarthrosis, the initial laboratory orders should include a bleeding score assessment, such as the ISTH BAT score, complete blood count (CBC), coagulation studies (PT/INR, PTT), factor assays (particularly Factor VIII and IX), von Willebrand factor testing, and inflammatory markers (ESR, CRP), as these tests are crucial in identifying the underlying cause of bleeding, which could be a bleeding disorder like hemophilia or von Willebrand disease 1.

When evaluating a patient with non-traumatic hemarthrosis, it is essential to consider the possibility of a bleeding disorder, and the laboratory workup should be guided by this suspicion. The use of a bleeding score, such as the ISTH BAT score, can help standardize the assessment of the bleeding phenotype, although recent studies suggest that age-dependent reference ranges should be employed, particularly in adult women 1.

Key laboratory tests to consider include:

• Complete blood count (CBC) to assess for anemia or thrombocytopenia
• Coagulation studies (PT/INR, PTT) to evaluate the extrinsic and intrinsic coagulation pathways
• Factor assays (particularly Factor VIII and IX) to diagnose specific factor deficiencies
• Von Willebrand factor testing to assess for von Willebrand disease
• Inflammatory markers (ESR, CRP) to evaluate for inflammatory arthritis or other conditions

Additionally, considering the patient's medical history, including any previous hemostatic challenges, and clinical gestalt is crucial in interpreting the laboratory results and guiding further testing 1. The exclusion of aspirin and nonsteroidal anti-inflammatory drug use is also relevant, as these drugs can affect platelet function and confound the assessment of bleeding disorders 1.

In terms of specific management strategies for non-traumatic hemarthrosis, tranexamic acid (TXA) is a commonly used adjunct in the management of bleeding disorders, and its use has been described in small series with a hemostatic efficacy of >90% 1. However, the quality of evidence is very low, and further studies are needed to inform practice.

Overall, the initial laboratory workup for non-traumatic hemarthrosis should be comprehensive and guided by the suspicion of a bleeding disorder, with a focus on identifying the underlying cause of bleeding and guiding appropriate treatment strategies 1.

From the FDA Drug Label

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. (1. 2) 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. (1. 3)

For non-traumatic hemarthosis, the lab orders may include tests to determine the underlying cause of the bleeding, such as:

• Factor VIII coagulant activity levels to diagnose Hemophilia A
• von Willebrand factor antigen and activity levels to diagnose von Willebrand's disease
• Complete Blood Count (CBC) to evaluate for other bleeding disorders
• Coagulation studies (e.g. prothrombin time, partial thromboplastin time) to assess the patient's coagulation status 2

From the Research

Lab Orders for Non-Traumatic Hemarthosis

• The initial laboratory tests for non-traumatic hemarthosis include a complete blood cell count, platelet count, prothrombin time, and activated partial thromboplastin time 3.
• An isolated prolongation of the activated partial thromboplastin time may indicate low levels of factors VIII, IX, or XI, while a slightly prolonged activated partial thromboplastin time and moderate decrease in factor VIII may suggest von Willebrand disease or the "carrier" state for hemophilia A 3.
• If von Willebrand disease is suspected, more specific laboratory tests such as assays of factor VIII, von Willebrand factor antigen, von Willebrand factor activity, and template bleeding time should be performed 3.
• For acquired hemophilia A, treatment with bypassing agents and immunosuppressive therapy may be recommended, with FVIII activity at presentation, inhibitor titer, and autoantibody isotype being prognostic markers for remission and survival 4.
• Bleeding disorder panels may include prothrombin time, activated partial thromboplastin time, fibrinogen level, and thrombin time, but these tests may have low sensitivity to clinically significant abnormalities, and expanded panels including von Willebrand disease screens and light transmission platelet aggregometry may be more effective in detecting bleeding disorders 5.

Laboratory Investigations

• Complete blood count reports and histograms can provide valuable information for diagnosing the etiology of anemia and bridging the time lag in detection and treatment 6.
• Automated hematology analyzers can detect anemias more efficiently, and timely interpretation of complete blood counts is essential for efficient patient care 6.
• Laboratory tests for bleeding disorders should be interpreted in the context of the patient's clinical presentation and medical history, and may involve a combination of screening tests and more specific assays to determine the underlying cause of the disorder 3, 4, 5.