Testing for Lyme Disease
Blood tests for Lyme disease can be inaccurate
The primary laboratory tests for Lyme disease are blood tests used to detect the antibodies created by your body to fight and kill the bacteria that causes Lyme. Blood tests for Lyme disease and co-infections may result in false negatives and false positives, and tests are not yet available for some of the many strains of Lyme or for some of the co-infections that may be acquired with or independently of Lyme.
Early in the infection with Lyme bacteria, antibodies may not have had time to develop in your body. Therefore, a blood test at this time will often appear negative. It can take your body up to two months to develop enough antibodies to be detected by these tests. You can still have Lyme even if test results come back indeterminate or negative.
Acute or disseminated Lyme disease is diagnosed based on clinical symptoms, in combination with laboratory tests and risk of exposure. There is much debate over the accuracy and reliability of the laboratory tests and the likelihood of false positives and false negatives.
The following tests are FDA-approved for diagnosis:
- The Enzyme-linked immunosorbent assay or ELISA is the first step. This test detects antibodies to B. burgdorferi and, if positive, is followed up by the Western Blot test.
- The western blot is usually run as a second-stage to confirm the diagnosis following a positive ELISA result. The Western blot detects antibodies to several proteins of B. burgdorferi. Together these tests are known as the ELISA/Western Blot.
- The polymerase chain reaction (PCR) is a highly sensitive test that detects DNA from the Borrelia bacteria in fluid drawn from an infected joint (typically synovial or cerebrospinal fluid). It is much less commonly used as the bacteria are most likely to bind to joint and nerve tissues and more difficult to detect.
The CDC states that their surveillance case definition was developed for national reporting of Lyme disease; it is not intended to be used in clinical diagnosis. According to the CDC, a diagnosis of Lyme disease should be based on symptoms.
A negative blood test for Lyme disease does not necessarily mean you are free from infection! There is currently no test that can confirm that bacteria has been cleared from the body, even after a patient has received treatment. If you have signs and symptoms of Lyme disease you may be infected, even if a blood test is negative.
For additional consideration when evaluating which tests to perform visit Dr. Daniel Cameron’s webpage.
There are several laboratories that specialize in the testing for Lyme and other tick-borne diseases.
Late-stage Lyme disease testing
The tests are the same regardless of the stage of Lyme disease. However, you cannot rely on test results alone. For reasons still unclear, some people infected with Lyme disease never mount an immune response detectable through antibody testing. There are also strains of Borrelia within the US for which testing has not yet been developed for commercial use, as well as strains in other regions of the world for which testing is not available in the US.
A positive Lyme test alone does not mean someone has active Lyme disease. It may mean that a person was infected in the past and the body produced antibodies that successfully eliminated the bacteria. Some viral illnesses or other infections can trigger the body to make certain antibodies against Lyme, even in the absence of a current infection. On the flip side, a negative test may not rule out Lyme disease, especially if symptoms are clinically significant for a Lyme infection.
Remember that a Lyme diagnosis is a clinical diagnosis that may be supported by laboratory tests.
Not all Colorado physicians have accurate information about diagnosing and treating Lyme disease. It is okay to ask your medical practitioner about their training, and how they choose to diagnose and treat Lyme and other tick-borne diseases. Colorado doctors may attend physician trainings that offer additional perspectives and information to consider in contrast with CDC/IDSA recommendations.
Those not receiving adequate care may wish to locate a doctor that is experienced in diagnosis, testing and treatment for Lyme and other tick-borne diseases.