The primary method for diagnosing pinworm (Enterobius vermicularis) infection is the 'cellophane tape test'. In this test, a sample taken from the perianal area with a clear piece of tape early in the morning is examined under a microscope to look for parasite eggs. Since pinworm eggs are rarely found in stool, a stool test is generally not effective. However, in some cases, adult pinworms may be visible to the naked eye in stool or around the anus. Microscopically detecting the eggs is fundamentally important for confirming the diagnosis.