False Positive Lyme Disease

A false positive Lyme disease result happens when a blood test shows antibodies that look like Lyme disease, but you don't actually have the infection. This can be confusing and stressful when you're trying to understand your health.

Lyme disease is caused by bacteria called Borrelia burgdorferi, which spreads through tick bites. Your immune system makes specific antibodies to fight this bacteria. However, other infections and health conditions can trigger similar antibodies. This cross-reactivity means your test might flag positive even when Lyme bacteria aren't present in your body.

False positives are more common than many people realize. They can happen with initial screening tests, which are designed to be very sensitive to catch all possible cases. That's why doctors use a two-step testing process. If your first test is positive, a confirmatory Western blot test helps rule out false positives and verify true Lyme disease.

• Confusion about test results that don't match how you feel
• Anxiety or worry after receiving a positive Lyme test
• Lack of typical Lyme symptoms like rash, fever, or joint pain
• Symptoms that better match another condition you already have
• No history of tick bites or time spent in Lyme-endemic areas
• Previous diagnosis of autoimmune disease or other infection

Many people with false positive results feel perfectly healthy. Others may have symptoms from a different condition entirely. The key is that test results don't align with your clinical picture or exposure history.

False positive Lyme tests happen when your immune system produces antibodies that look similar to Lyme antibodies. Other bacterial infections like syphilis and anaplasmosis can trigger this cross-reactivity. Autoimmune diseases such as lupus and rheumatoid arthritis also create antibodies that confuse Lyme screening tests. Some viral infections, including Epstein-Barr virus, may cause similar antibody patterns. Even certain vaccines can temporarily affect test results.

Your risk of a false positive increases if you have an existing autoimmune condition or chronic infection. Living in areas with low Lyme disease rates also raises the chance that a positive result is false. Testing too early after a tick bite, before your body makes enough antibodies, can also lead to confusing results. The screening test is designed to catch every possible case, which means it sometimes flags people who don't have Lyme disease.

Diagnosing a false positive requires looking at your test results alongside your symptoms, health history, and risk factors. The first step is a Lyme antibody screening test, which checks for antibodies your body makes against Lyme bacteria. If this test is positive, your doctor will order a Western blot confirmatory test. This second test is more specific and can tell the difference between true Lyme antibodies and similar antibodies from other conditions.

Rite Aid offers Lyme disease screening through our add-on testing options. You can add the Lyme Ab Screen to your blood panel and get tested at any Quest Diagnostics location near you. Your results will show whether follow-up testing is needed. Your doctor will review your complete clinical picture, including where you live, recent tick exposure, and current symptoms, to determine if your positive test is true or false.

• Confirmatory Western blot testing to verify or rule out true Lyme disease
• Clinical evaluation by a doctor familiar with Lyme disease and similar conditions
• Treatment for the actual underlying condition causing antibody cross-reactivity
• Management of autoimmune diseases with appropriate medications
• Antibiotics only if confirmatory tests and symptoms support true Lyme diagnosis
• Avoiding unnecessary antibiotic treatment if Lyme is ruled out
• Regular monitoring if you have chronic conditions that affect antibody levels
• Retesting after several weeks if initial timing was too early after exposure