Laboratory Testing and the Thrombophilia Workup

Surgeon General's Workshop on Deep Vein Thrombosis

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 SLIDE 1: Laboratory Testing and the Thrombophilia Workup

Thomas L. Ortel, M.D., Ph.D.
Duke University Medical Center
8 May 2006

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 SLIDE 2: Roles of the Clinical Laboratory

• Useful ancillary data for initial diagnosis (d-dimer).
• Monitoring antithrombotic therapy.
• Evaluation for underlying hypercoagulable state(s).
  • Identifies individuals 'at risk' for thrombosis.
  • Identifies individuals with an initial thrombosis who are at higher risk for recurrence.

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 SLIDE 3: What laboratory tests are useful in the acute setting?

• D-dimer (right arrow) supportive data to help rule out venous thromboembolism.
• Troponins/BNP (right arrow) stratify severity of PE.
• PT, aPTT (right arrow) essential baseline information prior to starting therapy.
• Hypercoagulable workup generally not useful in the acute setting.

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 SLIDE 4: Who should be considered for thrombophilia testing?

• Patients with unexplained, or 'idiopathic' thromboembolism.
• Patients with thromboembolism that is unusually extensive, or in an unusual location (e.g., portal vein thrombosis).
• Patients with a striking family history for venous thromboembolism.

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 SLIDE 5: What tests should be done?

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 SLIDE 6: Thrombophilic states and race

2 pie charts, 1 for Caucasian and 1 for African-American.

Caucasian

African-American

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 SLIDE 7: Thrombophilia in the pediatric patient

• Many studies include children with central venous lines and other acquired disorders.
• Elevated factor VIII and D-dimer is also associated with recurrent thrombosis

Pie chart.

Age: neonate to 18 yrs

Combined defects

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 SLIDE 8: Impact of thrombophilic disorders on recurrent thromboembolism

Line chart showing Impact of thrombophilic disorders on recurrent thromboembolism

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 SLIDE 9: ACCP Guidelines

2.1.4. For patients with first episode DVT and:

• • Antiphospholipid antibodies;
  • 2 or more thrombophilic conditions;
  • (right arrow) therapy for 12 months (1C+) or indefinite (2C).

2.1.5. For patients with first episode DVT and:

• • Antithrombin, protein C or protein S deficiency;
  • Factor V Leiden or prothrombin G20210A;
  • Elevated homocysteine or factor VIII levels
  • (right arrow) therapy for 6-12 months (1A) or indefinite (2C).

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 SLIDE 10: Cost of thrombophilia testing

* Duke Coagulation Laboratory

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 SLIDE 11: What should healthcare providers do with this information?

• Individuals who test positive for a thrombophilic risk factor require counseling as to:
  • risks of thrombosis to themselves and their family members.
  • importance of early recognition of signs and symptoms of venous thromboembolism.
  • risks and benefits of thromboprophylaxis in high-risk situations.

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 SLIDE 12: Should asymptomatic individuals be screened for thrombophilia?

• Screening of asymptomatic individuals, whether family members of a patient with thrombosis, or in a situation that places them at increased risk for thrombosis, is generally not recommended.
• However, in selected situations, knowledge of a specific thrombophilic state might guide therapeutic decision-making (e.g., decision concerning HRT usage).

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 SLIDE 13: On the other hand, one doesn't even need the doctor to order the test...

Photo of www.dnadirect.com

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 SLIDE 14: Future directions for thrombophilia testing

• Prospective clinical studies to define:
  • Role, if any, of screening asymptomatic family members or individuals in high-risk situations.
  • Impact on optimal therapy for patients with venous thrombosis and thrombophilia.
• Better education for providers as well as consumers concerning risk factors, prevention strategies, need for genetic counseling, etc.

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