What does a red glow during transillumination of a swollen testicle indicate?

• A. No glow indicates blood or tissue such as a hernia
• B. Red glow indicates serous fluid such as a hydrocele
• C. No glow indicates malignant tumor
• D. Green glow indicates infection

Answer: (B)

Transillumination helps distinguish fluid-filled from solid scrotal swellings. Light passing through clear serous fluid, as in a hydrocele, produces a red or pink glow. If the swelling contains solid tissue or bowel (as in a tumor or hernia with contents), light is blocked and there is little to no glow. Green glow isn’t a standard sign for infection. Therefore, a red glow indicates serous fluid such as a hydrocele.