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    Age-Adjusted D-dimer for Venous Thromboembolism (VTE)

    Adjusts D-dimer cutoffs by age to help rule out VTE.
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    INSTRUCTIONS

    Use in patients ≥50 years old presenting to emergency department as outpatients and are being worked up for PE with low to intermediate pretest probability. Do not use in high-risk patients (i.e., those who would proceed to imaging regardless of D-dimer result).

    When to Use
    Pearls/Pitfalls
    Why Use

    • Patients ≥50 years old presenting to emergency department as outpatients who are being worked up for PE and have low to intermediate pretest probability.

    • Do not use in high-risk patients (i.e., those who would proceed to imaging regardless of D-dimer result).

    • Has been shown to significantly increase specificity in older populations with minimal reduction in sensitivity.

    • Can be used for assays that report fibrinogen equivalent units (FEU) with a D-dimer cutoff of 500 µg/L, or D-dimer units (DDU, less common) with a D-dimer cutoff of 250 µg/L. 

    • A value below age x 10 µg/L (5 µg/L for DDU assays) adequately rules out the need for further testing for PE in low- to intermediate-risk patients.

    • Note that there is currently no standard D-dimer unit of measure, and there is wide variation among labs in cutoffs reported and magnitude of unit (e.g. µg/L vs ng/mL vs µg/mL).

    • While traditional teaching previously dictated that D-dimer should only be used in low-risk patients, this was based on lower sensitivity of D-dimer assays at the time. Modern D-dimer assays (immunoturbidimetric) have sensitivities up to 100% (Knecht 1997, Righini 2014).

    • This has been proposed to increase throughput time and decrease unnecessary testing and complications in patients.

    • Accepted by ACEP and ACP as acceptable in risk-stratifying low- to intermediate-risk patients.

    years
    Optional, for comparison if you have a D-dimer result
    µg/L
    FEU (unadjusted cutoff typically ~500 or 0.50)
    DDU (unadjusted cutoff typically 230-250 or 0.23-0.25)

    Result:

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    Next Steps
    Evidence
    Creator Insights

    Advice

    The goals of the age-adjusted D-dimer is to increase the specificity of the test in patients ≥50 years old and prevent unnecessary testing and complications.

    Use of the age-adjusted D-dimer is not appropriate for patients who are high-risk based on clinical gestalt or clinical prediction scores, such as the Wells’ Score for PE (scores >4) or Revised Geneva Score (scores >11).

    Management

    A patient with a D-dimer above the age-adjusted cutoff should undergo confirmatory testing with imaging (i.e., CTA, V/Q scan).

    Content Contributors
    • Indira Gowda, MD
    Reviewed By
    • Colin Bell, MD
    About the Creator
    Dr. Marc P. Righini
    Are you Dr. Marc P. Righini?
    Content Contributors
    • Indira Gowda, MD
    Reviewed By
    • Colin Bell, MD