Clots can form spontaneously or be provoked by conditions such as: Immobility Surgery and trauma Inflammation of the walls of the vein Family history Previous cases of DVT Cancer Acute Illnesses Blood Disorders Pregnancy While there are several symptoms of a DVT, imaging is necessary to diagnose the condition and help locate the clot. An ultrasound Doppler examination is a commonly used test to confirm whether a blood clot — or some other health problems — is causing your symptoms.