Neisseria Meningitidis Infections - Meningococcal Infections

How is the infection diagnosed?

Diagnosis of meningococcal infection begins with a medical history and physical exam. The Neisseria meningitidis bacteria can be found in the blood and spinal fluid. A sample of spinal fluid, which surrounds the brain and spinal cord, is obtained with a spinal tap.

A culture of blood or spinal fluid is often done. To do a culture, a sample of the fluid is put into a special container. Inside the container is something that is known as food to allow the bacteria to grow. If the bacteria grow, they can be identified in the lab. Culture of other infected areas, such as joint fluid or a piece of skin with a rash, can also be done.

A newer test called an antigen test can be done on the spinal fluid. This test can sometimes give results in less than an hour. But a culture may take as long as 24 hours to grow bacteria.