Understanding Your Laboratory Test: A Patient Guide

This test is a laboratory analysis that measures specific substances in a sample of your blood, urine, or other body fluid, helping your healthcare provider evaluate how well your body is functioning and detect possible health problems.

This test detects IgG and IgM antibodies against Borrelia burgdorferi, the bacterium that causes Lyme disease, in cerebrospinal fluid (CSF). CSF is the clear fluid that surrounds the brain and spinal cord. The test helps determine if Lyme disease has spread to the nervous system, a condition called neuroborreliosis.

Your doctor may order this test to help diagnose a medical condition, monitor an ongoing illness, check how well a treatment is working, or screen for potential health issues before symptoms appear.

Your healthcare provider may order this test if you have symptoms of Lyme disease that affect the nervous system, such as facial palsy, meningitis, limb weakness, or nerve pain. It is particularly useful when blood tests are inconclusive or when the infection is suspected to be limited to the central nervous system.

A trained healthcare professional will collect your sample, usually by drawing a small amount of blood from a vein in your arm or by asking you to provide a urine specimen in a sterile container.

Cerebrospinal fluid is collected through a procedure called a lumbar puncture, also known as a spinal tap. A healthcare provider inserts a thin needle into the lower back to withdraw a small amount of CSF. The procedure usually takes about 15-30 minutes. You may experience some discomfort or headache afterward.

Your results are compared with normal reference ranges. Values within the expected range usually suggest typical organ function, while abnormal values may indicate infection, inflammation, or another condition that requires follow-up testing.

Results are reported as positive or negative for IgG and IgM antibodies. IgM antibodies typically appear first (within 1-2 weeks of infection), while IgG antibodies develop later (within 4-6 weeks). A positive result in CSF indicates that the bacteria has potentially spread to the nervous system. However, results must be interpreted alongside your symptoms, exposure history, and other laboratory findings.

The risks are minimal. You may feel a brief sting during the needle stick and notice slight bruising or soreness afterward, but serious complications such as infection or excessive bleeding are very rare.

The main risks of lumbar puncture include headache, back pain, bleeding, or rare infection. Most people recover quickly with rest and hydration. Contact your healthcare provider if you experience severe headache, fever, or worsening pain after the procedure.