How is it Diagnosed?
Deep Vein Thrombosis (DVT) is diagnosed through a combination of clinical evaluation,
risk stratification, and imaging studies. DVT occurs when a blood clot forms in a deep
vein, typically in the legs, causing pain, swelling, and redness.
Initial assessment includes a thorough medical history focusing on recent surgery,
immobilization, cancer, hormonal therapy, or previous thrombotic events. Physical
examination findings such as unilateral leg swelling, tenderness along the deep venous
system, warmth, and Homans' sign (pain on dorsiflexion of the foot) may raise suspicion.
The Wells Score is commonly used to assess the clinical probability of DVT. Based on
this score, further diagnostic imaging is pursued. Compression ultrasonography is the
preferred initial imaging test. It detects thrombi by evaluating the compressibility of
veins—non-compressible veins suggest the presence of a clot.
If ultrasound findings are inconclusive and clinical suspicion remains high, a D-dimer
blood test is performed. Elevated D-dimer levels indicate increased fibrin degradation,
suggesting active clot formation and breakdown, although it lacks specificity. In low-risk
patients, a normal D-dimer can effectively rule out DVT.
In complex cases or when pelvic vein thrombosis is suspected, venography or magnetic
resonance venography (MRV) may be required. Duplex Doppler ultrasound is another
valuable tool combining real-time imaging and flow analysis.
Prompt and accurate diagnosis is essential, as untreated DVT can lead to lifethreatening pulmonary embolism.