An affected foot

Diagnosing Gout

Gout is a form of inflammatory arthritis caused by high levels of uric acid, a substance created by the body while breaking down purines found in seafood and steak. Sharp urate crystals form in the joints and nearby tissues, causing pain, swelling, and inflammation—especially in the big toe.

These periods of pain, known as gout attacks, may last days or weeks and appear rarely or chronically. There are several treatment options available to help manage not only the pain but the levels of uric acid in the blood. But to treat gout appropriately, an accurate diagnosis is the first step. Here’s a look at how gout is diagnosed.

Joint Fluid Testing

With several types of inflammatory arthritis floating around, the first step is to determine if other forms can be ruled out. The crystals that form in the joints are the key to this process. Joint fluid tests allow doctors to remove a small amount of fluid to be examined for urate crystals with a microscope.

As gout progresses, tophi may also form. These are lumps under the skin where urate crystals have gathered. Although they are generally not painful, they can be unsightly and indicative of advanced gout.

Blood Testing

Another means of determining if gout is present is blood testing. This can be tricky, though. Some people may have high amounts of uric acid and never have gout. Additionally, some patients may develop gout despite having normal levels of uric acid—the kidneys simply cannot flush uric acid out of the body through the urine. As such, blood tests can be useful, but it’s important to conduct other forms of testing as well to get an accurate picture of how treatment should progress.

Image Testing

Different types of imaging tests can help form a clear diagnosis as well. Radiographs, or x-rays, can be useful to determine if the swelling of the joints has a different cause. Additionally, they can show damage that may or may not be occurring in the joints of someone who has been dealing with gout for a long time.

Ultrasounds use soundwaves to create a real-time image of what’s going on inside the affected joints. Although they are not used as commonly to diagnose gout in the United States, they can provide a picture of the actual presence of urate crystals.

Dual energy computerized tomography scanning is also less popular because of the expense required to perform the test, but it too can show if there are urate crystals in the joints. If you think you may have developed gout, talk to your doctor about your options as soon as possible.

Last Updated: April 18, 2018