Diagnosis of Pseudogout
A diagnosis of pseudogout is based on physical symptoms and medical tests. Other conditions (e.g., injury, infection, rheumatoid arthritis) must be ruled out.
To confirm the diagnosis, the physician inserts a needle into the joint to obtain a sample of joint fluid, which is then analyzed under a microscope. Calcium pyrophosphate dihydrate (CPPD) crystals have specific characteristics, including shape and color, upon microscopic evaluation. Evaluation of the joint fluid may also show an increased level of white blood cells. In pseudogout, however, this level is not high enough to indicate joint infection.
X-rays of the affected joints can be used to detect complications caused by pseudogout (e.g., calcification of cartilage, joint degeneration). Standard x-rays include images of the knees, pelvis, wrists, and hands.