I had a discography to confirm a bad disc before having surgery to remove it. When the surgery was done, they didn't find anything wrong with the disc. The doctor said the test was a "false-positive." Why wasn't the test accurate?

Discography is often used in making a final diagnosis of low back pain. A dye is injected into the disc causing immediate pain when there's a problem. But there are no set and fast guidelines for what is a "true positive" or "true negative" test.

In fact, a recent study of discography showed 25 percent of the population tested had a false-positive when they weren't even having back problems. That same study found a high correlation between psychologic factors and false-positive discography results.

It seems there may be some people who are just more sensitive to anything that can cause pain even if there's nothing wrong. You may be one of those people. There are other explanations offered for false-positive discography, but the bottom line is that better, more accurate tests are needed to identify the cause of low back pain.