Immunoglobulin G (IgG) in cerebrospinal fluid (CSF) by mass concentration

Why Is This Test Done?

Your healthcare provider may order this test to check for infections, inflammation, or other conditions that affect the central nervous system, such as multiple sclerosis, meningitis, or certain types of brain tumors. It can also help diagnose or monitor conditions like Guillain-Barré syndrome or certain autoimmune diseases.

What Does It Measure?

IgG in CSF is measured to see if it’s higher or lower than expected. Elevated levels may suggest an immune response in the brain or spinal cord, while abnormal patterns could indicate conditions like demyelination or infections.

Sample Collection and Preparation

A small amount of cerebrospinal fluid is collected through a procedure called a lumbar puncture (spinal tap). The fluid is then sent to the lab for testing. This test is typically done when you’re awake and comfortable, but you may need to fast or avoid certain activities beforehand.

What Might Abnormal Results Mean?

Results may show elevated IgG levels if there’s an immune reaction in the CSF, such as in multiple sclerosis or certain infections. Low or unusual patterns could indicate conditions like brain tumors, infections, or other neurological disorders. Your provider will discuss these findings with you.