What is the appropriate work‑up for a febrile patient suspected of deep‑vein thrombosis and pulmonary embolism?

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Last updated: February 15, 2026 • View editorial policy

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Work-Up for Deep Vein Thrombosis and Pulmonary Embolism

Begin by assessing clinical probability using a validated scoring system (Wells or revised Geneva score), then proceed with D-dimer testing only in low-to-intermediate probability patients, reserving imaging for those with elevated D-dimer or high clinical probability. 1, 2

Step 1: Immediate Clinical Assessment

Hemodynamic Status

  • Assess for hemodynamic instability immediately—systolic blood pressure <90 mmHg or a drop ≥40 mmHg lasting >15 minutes identifies high-risk PE requiring emergent management. 1
  • In hemodynamically unstable patients with suspected massive PE, perform bedside echocardiography as the most useful initial test, which reveals indirect signs of acute pulmonary hypertension and right-ventricular overload. 1
  • Start therapeutic anticoagulation immediately in unstable patients based on echocardiographic findings alone, then obtain definitive imaging (CTPA) once stabilized. 1

Vital Signs and Key Clinical Features

  • Measure respiratory rate—tachypnea >20 breaths/min is a critical finding that significantly raises PE probability. 1, 2
  • Document heart rate—tachycardia ≥95 beats/min increases clinical probability. 1
  • Do not rely on oxygen saturation to exclude PE; up to 40% of PE patients have normal SaO₂. 1, 2
  • Obtain chest X-ray, ECG, and arterial blood gas in all suspected cases, though these are primarily to exclude alternative diagnoses. 1, 2

Step 2: Clinical Probability Stratification

Use Validated Scoring Systems

  • Apply the Wells score or revised Geneva score to categorize patients into low (<15%), intermediate (15-40%), or high (>40%) clinical probability before any laboratory testing. 1, 2

Wells Score for DVT includes:

  • Active cancer (+1)
  • Paralysis/recent immobilization (+1)
  • Bedridden >3 days or major surgery within 4 weeks (+1)
  • Localized tenderness along deep venous system (+1)
  • Entire leg swelling (+1)
  • Calf swelling >3 cm compared to asymptomatic leg (+1)
  • Pitting edema confined to symptomatic leg (+1)
  • Collateral superficial veins (+1)
  • Alternative diagnosis as likely or more likely (-2) 3

Revised Geneva Score for PE includes:

  • Previous PE or DVT (+3)
  • Heart rate 75-94 bpm (+3) or ≥95 bpm (+5)
  • Surgery or fracture within past month (+2)
  • Hemoptysis (+2)
  • Active cancer (+2)
  • Unilateral leg pain (+3)
  • Pain on deep venous palpation and unilateral edema (+4)
  • Age >65 years (+1) 1

Step 3: D-Dimer Testing (Selective Use Only)

When to Order D-Dimer

  • Order D-dimer ONLY after clinical probability assessment and only in low or intermediate probability patients. 1, 2
  • Do NOT order D-dimer in high clinical probability patients—proceed directly to imaging, as a negative D-dimer does not reliably exclude PE in this group. 1, 2
  • Avoid D-dimer testing in hospitalized patients, post-surgical patients, pregnant women, cancer patients, or those with active infection/sepsis—false-positive rates exceed 10% regardless of VTE status. 1, 3

D-Dimer Interpretation

  • Use highly sensitive assays (ELISA-based: Vidas, MDA, or SimpliRED for low probability only). 1
  • Standard cutoff: <500 ng/mL (or μg/L) safely excludes VTE in low/intermediate probability patients. 1, 3
  • Age-adjusted cutoff for patients >50 years: age × 10 ng/mL—this improves specificity from 10% to 35% in elderly patients while maintaining >97% sensitivity. 1, 3
  • A negative D-dimer in low or intermediate probability patients excludes VTE—no further testing required. 1, 2
  • A positive D-dimer cannot diagnose VTE—always proceed to imaging for confirmation. 1, 3

Step 4: Imaging Strategy

For Suspected DVT

Low Clinical Probability:

  • If D-dimer negative → stop, no DVT. 3
  • If D-dimer positive → proximal compression ultrasound (CUS) or whole-leg ultrasound. 1, 3
  • If proximal CUS negative → repeat in 1 week or perform whole-leg ultrasound. 3
  • If whole-leg ultrasound negative → stop, no further testing needed. 3

Intermediate Clinical Probability:

  • Proceed directly to whole-leg ultrasound or proximal CUS. 3
  • If whole-leg ultrasound negative → stop. 3
  • If proximal CUS negative → repeat in 1 week. 3

High Clinical Probability:

  • Proceed directly to proximal CUS or whole-leg ultrasound without D-dimer testing. 1, 3
  • If positive → treat immediately. 3
  • If negative → consider repeat imaging or alternative modalities (CT/MR venography). 3

For Suspected PE

Low Clinical Probability:

  • Apply PERC rule first (8 criteria: age <50, HR <100, SaO₂ ≥95%, no hemoptysis, no estrogen use, no prior VTE, no unilateral leg swelling, no surgery/trauma requiring hospitalization within 4 weeks). 1
  • If all PERC criteria met → stop, no PE (risk 0.3%). 1, 2
  • If any PERC criterion positive → obtain D-dimer. 1
  • If D-dimer negative → stop, no PE. 1, 2
  • If D-dimer positive → CT pulmonary angiography (CTPA). 1, 2

Intermediate Clinical Probability:

  • Obtain D-dimer (do not use PERC). 1
  • If D-dimer negative → stop, no PE. 1
  • If D-dimer positive → CTPA. 1, 2
  • Start therapeutic anticoagulation immediately while awaiting imaging. 1, 2

High Clinical Probability:

  • Proceed directly to CTPA without D-dimer testing. 1, 2
  • Start therapeutic anticoagulation before imaging confirmation. 1, 2

CTPA Interpretation

  • A normal CTPA in low/intermediate probability patients definitively excludes PE—no further testing needed. 1, 2
  • Segmental or more proximal filling defect confirms PE. 1
  • In high clinical probability patients with negative CTPA, consider additional imaging (leg ultrasound, conventional pulmonary angiography) or specialist consultation. 1

Alternative Imaging: V/Q Scanning

  • Use V/Q scan only when:
    • CTPA is contraindicated (renal failure, contrast allergy, pregnancy)
    • Chest X-ray is normal
    • No significant concurrent cardiopulmonary disease
    • Standardized reporting available 1, 2

V/Q Scan Interpretation:

  • Normal scan → PE excluded. 1
  • Low-probability scan + low clinical probability → PE excluded. 1
  • High-probability scan + high clinical probability → PE present. 1
  • All other combinations → require CTPA or conventional pulmonary angiography. 1

Lower-Extremity Ultrasound in PE Work-Up

  • Perform compression ultrasound before CT imaging in patients with:
    • Clinical signs of DVT
    • Renal failure
    • Contrast allergy
    • Pregnancy 1
  • If proximal DVT confirmed → treat for VTE without pulmonary imaging. 1
  • If ultrasound normal but D-dimer elevated → proceed to lung imaging (50% of PE patients have normal leg ultrasound). 1

Step 5: Immediate Anticoagulation

When to Start Heparin

  • Initiate therapeutic anticoagulation immediately in intermediate or high clinical probability patients before imaging confirmation—this reduces early mortality. 4, 1, 2

Choice of Anticoagulant

Hemodynamically Stable (Non-Massive PE/DVT):

  • Low-molecular-weight heparin (LMWH) is preferred over unfractionated heparin for equivalent efficacy and safety with greater ease of use. 4, 5
  • Direct oral anticoagulants (rivaroxaban, apixaban) can be started immediately in appropriate patients. 2, 5

Hemodynamically Unstable (Massive PE):

  • Unfractionated heparin (UFH): 80 units/kg IV bolus, then 18 units/kg/hour infusion, targeting aPTT 1.5-2.5 times control. 4, 2
  • UFH is preferred when rapid reversal may be required or in severe renal insufficiency. 5

Thrombolytic Therapy

  • Consider systemic thrombolysis only in hemodynamically unstable patients (massive PE) with low bleeding risk. 4, 2, 5
  • Regimens: rtPA 100 mg over 2 hours, or streptokinase 250,000 units over 20 minutes followed by 100,000 units/hour for 24 hours. 4

Common Pitfalls to Avoid

  • Never use D-dimer as a routine screening test—order only after clinical probability assessment. 1, 2
  • Never order D-dimer in high-probability patients or hospitalized patients with comorbidities—low diagnostic yield and high false-positive rates. 1, 3
  • Never rely on normal oxygen saturation to exclude PE—40% of PE patients have normal SaO₂. 1, 2
  • Never order V/Q scan when chest X-ray is abnormal or patient has chronic cardiopulmonary disease—results will be non-diagnostic. 1
  • Never use a positive D-dimer alone to diagnose VTE—confirmation with imaging is always required. 1, 3
  • Never delay anticoagulation in intermediate/high probability patients while awaiting imaging—significantly increases mortality. 1, 2
  • Imaging for massive PE should be performed within 1 hour; for non-massive PE, within 24 hours. 4, 1, 2

References

1
Guideline

Pulmonary Embolism Diagnosis and Management

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2026

2
Guideline

Diagnosis and Management of Suspected Pulmonary Embolism

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2025

3
Guideline

D-Dimer Testing in Suspected Deep Vein Thrombosis

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2026

4
Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

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Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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