CRPS: Diagnosis
Diagnosing CRPS can be very difficult. Unfortunately, there is no single laboratory test to diagnose the disorder. Your doctor will need to conduct a thorough medical history and physical examination. You can help by providing a list of any treatments you have received and your response to them, as well as a summary of any hospitalizations and surgeries.

Your doctor will first need to rule out other potentially life-threatening disorders that may have similar clinical features. For example, a blood clot in a leg vein or a breast tumor spreading to lymph glands can cause a swollen, painful extremity. In fact, CRPS may be associated with another disease or disorder, (e.g. a herniated disc of the spine, carpal tunnel syndrome, heart attack).

There are several diagnostic tests that may help in diagnosing CRPS or ruling out other disorders. A thermogram is probably one of the most widely used tests. It measures heat emission from the body surface using a special infrared video camera.

Your neurologist may request additional testing including X-rays, EMG, Nerve Conduction Studies, CAT scan and Magnetic Resonance Imaging (MRI) studies to help exclude or identify other possible causes of pain.