The evaluation of deep venous thrombosis begins with a medical history and physical examination.

Physical findings in someone with a deep venous thrombosis may include:

• Leg swelling (unilateral)
• Calf tenderness
• Thigh tenderness

Tests are usually done to confirm the diagnosis of deep venous thrombosis.

Tests that may be used to evaluate deep venous thrombosis include:

• D-dimer assay:
• A blood protein that is elevated in people with deep venous thrombosis.
• Angiodynography
• Duplex ultrasound:
• Now the diagnostic method of choice due to its high accuracy and low risk of complications
• MRI scanning of the pelvis:
• Can accurately detect clots within the renal veins and pelvis
• Other methods for imaging clots include:
• Impedance plethysmography
• Radiolabeled fibrinogen (nuclear scan)
• Venogram:
• An x-ray is taken of the veins