Cerebrospinal Fluid Immunoglobulin Isotype Quantification (IgG, IgA, IgM)

Why This Test Might Be Ordered

Your doctor may recommend this test if you have symptoms like headaches, neck stiffness, confusion, or neurological issues that suggest an infection, autoimmune disease, or other condition affecting the brain or spinal cord. It’s often used alongside other tests to diagnose conditions such as multiple sclerosis, meningitis, or certain types of brain tumors.

What to Expect Before the Test

You’ll likely have a small needle inserted into your lower back to collect a sample of CSF. This procedure, called a lumbar puncture or spinal tap, may cause mild discomfort but is generally quick and safe. You may be asked to lie on your side for a few hours afterward to avoid headaches.

What the Results Mean

Abnormal Ig levels in CSF can signal an immune response, infection, or other neurological conditions. For example, elevated IgG might suggest a demyelinating disease, while unusual IgA or IgM patterns could indicate certain infections or inflammatory processes. Your doctor will interpret results in the context of your symptoms and other tests.

Common Conditions This Test Helps Diagnose

This test is often used to diagnose or monitor conditions like multiple sclerosis, meningitis (including viral or bacterial), Guillain-Barré syndrome, and certain types of brain tumors or autoimmune diseases affecting the central nervous system.