What is the initial workup for a patient presenting with abnormal bruising?

Initial Workup for Abnormal Bruising

The initial laboratory evaluation for patients with abnormal bruising should include a complete blood count (CBC) with platelet count, prothrombin time (PT), activated partial thromboplastin time (aPTT), von Willebrand factor antigen (VWF:Ag), von Willebrand factor ristocetin cofactor activity (VWF:RCo), and factor VIII coagulant activity (FVIII). 1

Clinical Assessment Elements

Before laboratory testing, focus on these key clinical elements:

• Bleeding history: Document specific bleeding symptoms including:

  • Epistaxis (frequency, duration, need for medical intervention)
  • Easy bruising (location, size, frequency, triggering events)
  • Menorrhagia (pad/tampon usage, flooding, clots)
  • Post-surgical or dental bleeding
  • Family history of bleeding disorders

• Medication review: Identify medications affecting hemostasis:

  • Anticoagulants
  • Antiplatelet agents
  • NSAIDs
  • Certain antibiotics
  • Herbal supplements

• Physical examination: Look for:

  • Distribution of bruising (suspicious locations vs. common areas)
  • Petechiae (suggesting platelet disorders)
  • Joint swelling (suggesting coagulopathy)
  • Mucosal bleeding (suggesting platelet dysfunction)

Laboratory Evaluation Algorithm

First-Line Testing:

1. CBC with platelet count

   • Evaluates for thrombocytopenia or other hematologic abnormalities
   • Low platelets suggest ITP or other platelet disorders

2. PT and aPTT

   • PT: Assesses extrinsic and common pathways
   • aPTT: Evaluates intrinsic and common pathways
   • Interpretation:
     • Normal PT/aPTT with abnormal bleeding: Consider platelet disorder or von Willebrand disease
     • Prolonged PT, normal aPTT: Consider factor VII deficiency or vitamin K deficiency
     • Normal PT, prolonged aPTT: Consider hemophilia A/B or factor XI/XII deficiency
     • Both prolonged: Consider multiple factor deficiencies, liver disease, or DIC

3. VWF:Ag, VWF:RCo, and FVIII

   • Essential for diagnosing von Willebrand disease, the most common inherited bleeding disorder 1
   • VWF:RCo/VWF:Ag ratio <0.5-0.7 suggests qualitative VWF defect (Type 2 VWD)

Additional Testing Based on Initial Results:

• If thrombocytopenia present: Peripheral blood smear to evaluate platelet morphology
• If prolonged aPTT: Perform mixing study to distinguish factor deficiency from inhibitor
• If prolonged PT: Consider vitamin K challenge test
• If normal initial tests but high clinical suspicion: Consider specialized platelet function testing

Special Considerations

• Sample collection: Ensure atraumatic blood draw to prevent activation of clotting factors 1
• Timing: Avoid testing during stress, exercise, inflammation, pregnancy, or while on estrogen, as these can elevate VWF and FVIII levels 1
• Repeat testing: Single normal test results don't exclude bleeding disorders; consider repeat testing if clinical suspicion remains high 1
• Pediatric considerations: In children with suspicious bruising, consider both bleeding disorders and non-accidental trauma 2

When to Refer to Hematology

• Abnormal initial testing results
• Strong clinical suspicion despite normal initial testing
• Need for specialized testing (platelet aggregation studies, factor assays)
• Confirmed bleeding disorder requiring management

Common Pitfalls

• Relying solely on PT/aPTT to exclude bleeding disorders (will miss von Willebrand disease)
• Failure to consider medication effects on test results
• Testing during physiologic states that alter coagulation parameters
• Improper sample collection or handling affecting results
• Dismissing concerns without adequate evaluation when initial tests are normal

Remember that von Willebrand disease is the most common inherited bleeding disorder, yet it may present with normal PT and aPTT, making the VWF-specific testing essential in the initial evaluation of abnormal bruising 1, 3.