Lyme Disease Testing Guide

Lyme disease testing checks for the bacteria Borrelia burgdorferi, which is spread through the bite of infected deer ticks. Testing is done with a blood test that looks for antibodies, and it measures two types, IgM and IgG, which appear at different stages of infection. IgM antibodies show up in the first weeks after infection, while IgG antibodies develop later and persist longer, indicating a more established infection. Because antibodies take time to develop, testing too early can give a false negative result, so timing matters. The CDC recommends a two-step testing process for diagnosis. This guide explains how the IgG and IgM tests work and what your results mean.

How Lyme Disease Spreads

Lyme disease is transmitted by the bite of an infected blacklegged tick, commonly called a deer tick. The tick must usually be attached for a period of time to transmit the bacteria, and prompt removal lowers the risk. The disease most often occurs in certain regions during the warmer months.

Not every tick bite causes Lyme disease, and not every person bitten develops it. Because diagnosis is based on a combination of symptoms, exposure, and test results, a tick bite alone does not mean infection, and not everyone remembers a bite.

Early Signs and Symptoms

The early sign of Lyme disease is often a distinctive rash called erythema migrans, which looks like an expanding red ring or bullseye at the site of the bite, usually within 3 to 30 days. It is accompanied in many cases by fever, chills, fatigue, headache, and muscle and joint aches.

These early symptoms can resemble the flu and may appear without the rash. Untreated, the infection can spread to the nervous system, joints, and heart in later weeks or months, which is why early testing and treatment matter.

Getting Tested: Two-Step Approach

The CDC recommends a two-step testing process. The first step is an enzyme immunoassay, or EIA, test. If it is negative, no further testing is needed. If it is positive or equivocal, a second step, a Western blot test, is done to confirm, and the Western blot looks at IgM and IgG antibody bands.

IgM antibodies appear within the first few weeks and support a recent infection, while IgG antibodies appear later and indicate a more established infection. Testing within the first two weeks of infection can be falsely negative because antibodies have not yet formed, so the ideal timing depends on symptoms and exposure.

Understanding Results and Treatment

A positive test supports the diagnosis of Lyme disease, and the pattern of IgM and IgG bands guides whether it is an early or established infection. Some people who were treated or exposed long ago still show IgG antibodies, which is expected. Negative results in the right window and with an appropriate test reduce the likelihood of infection.

When diagnosed, Lyme disease is treated with antibiotics, with the best outcomes when treatment begins early. If you have symptoms or a recent suspected tick bite, testing at the right time, combined with a clinician's assessment, is the reliable path to diagnosis and recovery.

Order Lyme Disease IgG and IgM Test Online