Lyme disease: Test and Diagnosis
June 1, 2012
Lyme disease has many nonspecific symptoms that often are found in other conditions, such as viral infections, various joint disorders, fibromyalgia, chronic fatigue syndrome and even depression. Sometimes, these common conditions are misdiagnosed as Lyme disease. What's more, the ticks that transmit Lyme disease also can spread other diseases at the same time.
If you don't have the characteristic Lyme disease rash, your doctor may ask detailed questions about your medical history and do a physical exam. Lab tests to identify antibodies to the bacteria may be used to help confirm the diagnosis. These tests are most reliable a few weeks after an infection, after your body has time to develop antibodies. They include:
- Enzyme-linked immunosorbent assay (ELISA) test. The test used most often to detect Lyme disease, ELISA detects antibodies to B. burgdorferi. But because it can sometimes provide false-positive results, it's not used as the sole basis for diagnosis.
- Western blot test. If the ELISA test is positive, another test — the Western blot — is usually done to confirm the diagnosis. The Western blot detects antibodies to several proteins of B. burgdorferi.
- Polymerase chain reaction (PCR). This test helps detect bacterial DNA in fluid drawn from an infected joint. It's not as effective at detecting infection of blood or urine. It's used for people who may have chronic Lyme arthritis. It may also be used to detect persistent infection in the cerebrospinal fluid of people who have nervous system symptoms.