How is sciatica diagnosed?

To help diagnose sciatica and pinpoint which nerves, if any, are affected, your doctor will use these approaches:

• Medical history. Your doctor will ask about your medical history.
• Physical exam. Your doctor will perform a thorough physical exam, paying special attention to your spine and legs.
• Basic muscle tests. Likely, your doctor will have you undergo some basic tests that check your muscle strength and reflexes. For example, you may be asked to walk on your toes or heels, rise from a squatting position and, while lying on your back, lift your legs one at a time straight in the air. Pain that results from sciatica will usually become worse during these activities.

Sciatica is a clinical diagnosis. In other words, the doctor will be able to make the diagnosis based on your medical history, a physical examination, and your description of your symptoms. If you have had sciatica for only a brief time and you have no sign of any other diseases, no lab studies or X-ray films may be needed.

• If the pain has been present for several weeks, you may get special studies of your back: either CT (computerized tomography) or MRI (magnetic resonance imaging) scans.
  
• If you have a history of cancer, HIV infection, IV drug use, or you have been taking steroids over a period a time, the doctor may want to see plain X-ray films of your back or a bone scan
• Occasionally, laboratory studies may be helpful. A CBC (complete blood count) may suggest infection, anemia due to certain cancers, or other unusual causes of sciatica. Elevated sedimentation rate may suggest inflammation somewhere in the body. Urinalysis can suggest a kidney stone, if there is blood in the urine, or infection, if there are bacteria and pus in the urine.