Venous Thromboembolism Clinical Practice Guidelines (2019)

In November 2018, the American Society of Hematology (ASH) released guidelines for the diagnosis of venous thromboembolism (VTE).^[1] The American Academy of Family Physicians endorsed these guidelines in March 2019 and provided the following key recommendations from the guidelines.^[2]

D-dimer testing alone should not be used to rule in or diagnose a PE, and a positive D-dimer alone should not be used to diagnose DVT.

Pulmonary Embolism (PE)

Individuals with a low or intermediate pretest probability or prevalence: Clinicians should use a D-dimer strategy to rule out PE, followed by a ventilation-perfusion (VQ) scan or computed tomography pulmonary angiography (CTPA) in patients requiring additional testing. D-dimer testing alone should not be used to rule in a PE.
Individuals with a high pretest probability or prevalence (≥50%): Clinicians should start with CTPA to diagnose PE. If CTPA is not available, a VQ scan should be used with appropriate follow-up testing.
Individuals with a high pretest probability/prevalence: D-dimer testing alone should not be used to diagnose PE and should not be used as a subsequent test after CT scanning.
Individuals with a positive D-dimer or likely pretest probability: CTPA should be performed. D-dimer testing can be used to exclude recurrent PE in individuals with an unlikely pretest probability.
Outpatients older than 50 years: Use of an age-adjusted D-dimer cutoff is safe and improves the diagnostic yield. Age-adjusted cutoff = Age (years) × 10 µg/L (using D-dimer assays with a cutoff of 500 µg/L).

Lower Extremity (LE) Deep Vein Thrombosis (DVT)

Individuals with a low pretest probability or prevalence: Clinicians should use a D-dimer strategy to rule out DVT, followed by proximal LE or whole-leg ultrasonography in patients requiring additional testing.
Individuals with a low pretest probability or prevalence (≤10%): Positive D-dimer alone should not be used to diagnose DVT, and additional testing following negative proximal or whole-leg ultrasonography should not be conducted.
Individuals with an intermediate pretest probability or prevalence (~25%): Whole-leg or proximal LE ultrasonography should be used. Serial proximal ultrasonographic testing is needed after a negative proximal ultrasonogram. No serial testing is needed after a negative whole-leg ultrasonogram.
Individuals with suspected DVT and a high pretest probability or prevalence (≥50%): Whole-leg or proximal LE ultrasonography should be used. Serial ultrasonography should be used if the initial ultrasonogram is negative and no alternative diagnosis is identified.

Upper Extremity (UE) DVT

Individuals with a low prevalence/unlikely pretest probability: D-dimer testing should be used to exclude UE DVT, followed by duplex ultrasonography if findings are positive.
Individuals with a high prevalence/likely pretest probability: Either D-dimer testing followed by duplex ultrasonography/serial duplex ultrasonography, or duplex ultrasonography/serial duplex ultrasonography alone can be used for assessing patients suspected of having a UE DVT.
A positive D-dimer alone should not be used to diagnose UE DVT.

For more information, please go to Venous Thromboembolism (VTE).

For more Clinical Practice Guidelines, please go to Guidelines.

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