A spinal tap test can show an increase in antibodies in the central nervous system (CNS) and is often used to diagnose MS. Yet, 5 to 10% of people diagnosed with multiple sclerosis do not show increased antibodies in the CNS.
Also, many other inflammatory diseases and parasites are associated with increased antibodies in the CNS.
This post discusses spinal taps, what they are, how accurate they are and how an increased presence of antibodies in the CNS is a sign of a parasitic infestation.