It may be useful to keep a log of symptoms that occur, noting when they occur and for how long. It is especially important to report any flu-like symptoms (e.g. fever, vomiting, diarrhea) even if they were mild, since they may be indicators of a bacterial infection.
Various blood tests may be ordered to help rule out other conditions when ReA is suspected. The presence of rheumatoid factor or antinuclear antibodies indicate the person may have a different form of arthritis, such as rheumatoid arthritis or lupus.
Other tests may be ordered to check for infections commonly associated with ReA. Testing for the presence of Chlamydia is important, as studies show that early treatment of Chlamydia-induced ReA may reduce the progression of the disease.
A doctor may look for bacterial infections by testing cell samples from the patient’s throat, urethra, or cervix. Urine and stool samples also may be tested. A sample of synovial fluid (the fluid that lubricates the joints) may be removed from an arthritic joint and tested to rule out infection in the joint.
X-rays may also be ordered to determine sacroiliac involvement, swelling of the soft tissues, damage to cartilage, and bone deposits where the tendon attaches to the bone.