Cerebrospinal Fluid Immunoglobulin G (IgG) Index (Mass Concentration)

Why Is This Test Done?

Your doctor may order this test if you have symptoms like numbness, weakness, vision problems, or balance issues that could suggest nerve or brain inflammation. It’s also used to monitor conditions like multiple sclerosis, Guillain-Barré syndrome, or other autoimmune disorders affecting the central nervous system.

What Does the Result Mean?

An elevated IgG index in CSF may suggest an immune response within your brain or spinal cord, potentially due to conditions like multiple sclerosis, infections, or other inflammatory processes. A normal result doesn’t rule out all possible causes, so your doctor will consider other test results and symptoms.

Sample Collection and Preparation

A small amount of CSF is collected through a procedure called lumbar puncture (spinal tap). The sample is then analyzed in a lab to measure IgG levels. This test is typically done after other diagnostic tests, such as MRI or blood tests, to provide more context.

Common Conditions Monitored

This test is often used to diagnose or monitor conditions like multiple sclerosis, neuromyelitis optica, or other demyelinating diseases. It may also help identify infections (e.g., Lyme disease, tuberculosis) or autoimmune reactions affecting the central nervous system.