InstalabLyme Disease Antibodies
Should you take a Lyme Disease Antibodies test?
This test is most useful if any of these apply to you.
2 Biomarkers Included
- Lyme Antibody (IgG)The slower, longer-lasting responder. It builds over weeks and can persist for years, so it carries most of the diagnostic weight in later-stage disease and signals that an infection is not brand new.A positive IgG means exposure, but it cannot separate an active infection from one your body cleared years ago.
- Lyme Antibody (IgM)The early responder. It usually appears within the first few weeks of infection, making it the marker most likely to flag a recent case before the slower antibody catches up.A positive IgM on its own is often a false alarm, especially more than six weeks after a possible bite.
About Lyme Disease Antibodies
Lyme disease is easy to miss. The tick bite is usually painless, the rash does not always appear, and the earliest symptoms can look like a summer flu. This panel gives you a way to check whether an infection took hold, by reading the antibody trail your immune system leaves behind.
It pairs two antibody measurements that answer different questions. One tends to rise first, in the earliest weeks, while the other rises later and lingers. Read together, they say more about the timing of an infection than either one can alone.
What This Panel Reveals
Your body fights the Lyme bacterium (Borrelia burgdorferi) by making antibodies, which are proteins that tag one specific invader. This panel measures two classes of them. The first, called IgM (immunoglobulin M), is the rapid early responder that usually appears within the first few weeks. The second, called IgG (immunoglobulin G), builds more slowly and can stay in your blood for years.
Neither test looks for the bacteria directly. They detect your immune response to it, which is why timing matters so much. In the first weeks of infection the antibody trail is still faint, and standard two-tier testing catches only about 30% to 40% of cases during this window. Once the infection has spread beyond the skin, that figure rises to roughly 70% to 100%, while the chance of a false positive in healthy people stays low.
How to Read Your Results Together
The value of ordering both antibodies is that the combination sketches a rough timeline. These antibody results carry the most weight when read within the standard two-step laboratory process, not as stand-alone numbers. Here is how the common patterns usually read.
| Your Pattern | Usual Meaning | The Catch |
|---|---|---|
| Both negative | No antibody evidence of infection | A very early infection can still test negative |
| IgM positive, IgG negative | Compatible with a recent, early infection | Alone, this is often a false positive, especially past six weeks |
| IgM positive, IgG positive | A more established or evolving response | It does not prove the infection is active right now |
| IgM negative, IgG positive | Later-stage or past infection | IgG can linger for years after a cured infection |
The pattern to treat with the most caution is a lone positive IgM. When that result stood by itself, one review found that about half of the resulting Lyme diagnoses were later judged incorrect, and a large health-system study found that 53.3% of positive IgM results were false positives, yet 80.5% of those people still received antibiotics. A positive IgM rarely moves on to a true IgG response later, which happened in only 0.23% of patients tracked over time.
What to Do with Your Results
A positive result is a starting point, not a verdict. Bring it to a clinician who can confirm it with the standard two-step laboratory process and weigh it against your symptoms and tick exposure. Reading a single antibody outside that two-step framework lowers its reliability. This matters most when your symptoms are vague or you have no clear history of a bite, since a positive test in that setting is more likely to be a false alarm.
If your symptoms are recent and both antibodies are negative, do not treat that as the final answer. Antibodies lag behind infection, so retesting in a few weeks is often worthwhile, and this is most informative before antibiotics are started. In one study of confirmed early cases, only 33% were positive at first, but 91% turned positive within one to two weeks of follow-up; once treatment has begun, a later shift to positive is less likely. If you may have been exposed to more than one tick-borne germ, a coinfection workup can round out the picture.
This panel is not a test of cure. Both antibodies can persist long after the bacteria are gone, with IgG detectable for a median of up to 8.8 years and IgM up to 6.8 years. Because of that, retesting to confirm that treatment worked is not useful, and a positive result years later does not mean the infection is still active.
When Results Can Be Misleading
A few situations can push both antibodies off course at once. A recent viral infection is a common one, because antibodies made against other germs can cross-react. In people with active Epstein-Barr virus (the cause of mono), one study saw false or borderline Lyme IgM in 22.2% of a standard screening assay and 11.1% of the confirmatory blot. Syphilis, relapsing-fever bacteria, and some autoimmune conditions can trigger similar cross-reactions. And because antibodies reflect exposure rather than active disease, a past infection or living in a high-tick region can leave you positive without current illness.