Skip Navigation
Text Size: A A A

Laboratory Testing and the Thrombophilia Workup

Surgeon General's Workshop on Deep Vein Thrombosis

1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14

Return to Menu


 SLIDE 1: Laboratory Testing and the Thrombophilia Workup

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

Return to Top

 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.

Return to Top

 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.

Return to Top

 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.

Return to Top

 SLIDE 5: What tests should be done?

  • Activated protein C resistance, with analysis for factor V Leiden if positive.
  • Prothrombin G20210A genotype analysis.
  • Antithrombin functional assay.
  • Protein C functional assay.
  • Protein S functional assay, with antigenic assays if indicated.
  • Antiphospholipid antibody testing.
  • Homocysteine level.
  • Factor VIII assay.

Return to Top

 SLIDE 6: Thrombophilic states and race

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

Caucasian

FVL14.5
PT G20210A8.2
AT deficiency1.9
PC deficiency3.7
PS deficiency2.3
Elevated FVIII25
APLA10
 34.4
African-American
FVL14.5
PT G20210A8.2
AT deficiency1.9
PC deficiency3.7
PS deficiency2.3
Elevated FVIII25
APLA10
 34.4

Return to Top

 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

FVL29.2
PT G20210A3.7
AT deficiency1.7
PC deficiency6.6
PS deficiency1.3
Elevated Lp(a)14.9
Combined defects20.9
 21.7

Return to Top

 SLIDE 8: Impact of thrombophilic disorders on recurrent thromboembolism

Line chart showing Impact of thrombophilic disorders on recurrent thromboembolism

Return to Top

 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).

Return to Top

 SLIDE 10: Cost of thrombophilia testing

TestApproximate Cost*
Natural anticoagulants (antithrombin, protein C, protein S):$450-750
Genetic tests (factor V Leiden, prothrombin G20210A):$600
Antiphospholipid antibodies:$1000-1500
Other (factor VIII, homocysteine):$200
TOTAL:$2250-3050

* Duke Coagulation Laboratory

Return to Top

 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.

Return to Top

 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).

Return to Top

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

Photo of www.dnadirect.com

Return to Top

 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.

Return to Top