In a patient with suspected deep vein thrombosis, which approach optimizes decision making?

• A. Use a validated clinical probability score (e.g., Wells) to stratify risk, then decide on D-dimer vs imaging accordingly.
• B. Perform imaging in all patients regardless of probability.
• C. Rely solely on patient-reported symptoms.
• D. Start anticoagulation immediately without testing.

Answer: (A)

This question hinges on using a validated pretest probability assessment to guide the diagnostic workup for suspected DVT. By applying a score like Wells, you classify patients into low, intermediate, or high likelihood. In those with low probability, a negative D-dimer can safely exclude DVT, avoiding unnecessary imaging. In those with high probability, imaging—typically compression ultrasonography—should be pursued regardless of the D-dimer result, because the chance of DVT is high enough that a negative D-dimer wouldn’t reliably rule it out. The D-dimer test is most helpful in the intermediate-probability group, where a negative result can rule out DVT and a positive result prompts imaging. This approach balances sensitivity and specificity, reduces unnecessary imaging and its costs or potential harm, and minimizes delays in diagnosis. Relying solely on symptoms is unreliable because DVT can be asymptomatic or nonspecific; imaging all patients increases cost and may yield incidental findings; starting anticoagulation without testing risks bleeding and misdiagnosis.