History and examination are fairly conclusive in most cases helping us to reach a provisional diagnosis.
Colour Doppler study – This shows dilated veins with a sluggish flow or no flow. You can see a blood clot making the veins not compressible.
Blood tests – Most routine tests are normal but the D-dimer is elevated. D-dimer is a clot-dissolving substance.
Venography – The dye is injected into the foot vein and images of the dye in the veins of the leg are recorded. A filling defect denotes the occluded vein.