Tests and diagnosis

Your doctor will conduct a physical exam, which may reveal enlarged lymph nodes in your groin and an enlarged testicle on the affected side. Your doctor also may do a rectal examination to check for prostate enlargement or tenderness and order blood and urine tests to check for infection and other abnormalities.

Other tests your doctor might order include:

• STD screening. This involves obtaining a sample of discharge from your urethra. Your doctor may insert a narrow swab into the end of your penis to obtain the sample, which is then tested for the presence of bacteria or other infectious organisms. The results can be used to select the most effective antibiotic for treatment.
• Ultrasound imaging. This noninvasive test uses high-frequency sound waves to create images of structures inside your body and is used to rule out conditions such as twisting of the spermatic cord (testicular torsion) or a testicular tumor. Your doctor is likely to use this test if your symptoms began with sudden, severe pain. If the ultrasound shows increased blood flow to your testicle, it supports a diagnosis of epididymitis.
• Nuclear scan of the testicles. Also used to rule out testicular torsion, this test involves injecting trace amounts of radioactive material into your bloodstream. Special cameras then can detect areas in your testicles that receive less blood flow, indicating torsion, or more blood flow, supporting the diagnosis of epididymitis.