Diagnosis of Lyme Disease

Diagnosing Lyme Disease is difficult. Many of the signs and symptoms are found in other conditions as well. In addition, the ticks that transmit Lyme Disease also spread other diseases at the same time.

Lab Tests

Lab tests to identify antibodies to the bacteria in tick bites can help to confirm a diagnosis. These tests are most reliable a few weeks after infection. It takes time for your body to develop antibodies.Diagnosing Lyme Disease - 4-Word Bound

  1. Enzyme-Linked Immunosorbent Assay (ELISA) Test. This is the most frequently used test. It finds antibodies to burgdorferi. It cannot be used as a single basis for a diagnosis because it is known to return false-positive results in some instances. This test may not be positive during the early stages of Lyme disease, but the rash is distinctive enough to make a diagnosis without further testing in those people who live in areas infested with ticks that transmit Lyme Disease.
  2. Western Blot Test. If the Elisa test is positive, this test is typically used to confirm the diagnosis. It detects antibodies to several proteins of B Burgdorferi.

 

Clinical Diagnosis

Lyme Disease requires a clinical diagnosis, including your medical history, symptoms and amount of exposure to ticks. This is necessary because the typical diagnostic tests are so insensitive that a negative test result does not mean that you do not have Lyme Disease.

Why do false-negative results occur? There are three primary reasons:

  1. Enough time may not have elapsed for antibodies to develop.
  2. The immune system may be suppressed.
  3. You may be infected with a strain that is not measured by the test.

Consider these findings about the tests:

  • 20-30% of patients receive a false-negative result from antibody tests.
  • 56% of patients with Lyme Disease test negative using the two-tiered testing system recommended by the Centers for Disease Control (CDC).
  • The College of American Pathologists (CAP) found that ELISA tests do not have adequate sensitivity to be used for screening purposes.
  • 52% of patients with chronic Lyme Disease have a negative result by ELISA but a positive result by Western Blot.

In addition to helping physicians to diagnose a disease, the tests can help physicians to manage the illness. A good test can help a doctor assess the severity of the disease, estimate the patient’s prognosis, monitor the course of disease progression, stability or resolution, detect relapse, and select drugs or adjust the therapy.  Unfortunately, at this time there is no Lyme Disease test with these capabilities.

 

Other Tests

There are other tests for Lyme Disease that are called “direct tests.” These tests identify the bacteria, not just your immune response to it.

  1. Polymerase Chain Reaction (PCR) is antigen detection and culture testing. This test multiplies a critical amount of DNA from the Lyme bacteria in order to detect it. It is a very accurate test when the Lyme DNA is detected, but it produces many false-negatives because the Lyme bacteria are sparse and may not be in the specific sample tested.
  2. Antigen Detection Tests look for a unique Lyme protein in body fluids (blood, urine, joint fluid). Some patients who test negative on indirect tests will return a positive result on this test.
  3. Culture is the “gold standard” test for identifying bacteria. However, the CDC has advised caution when using this only commercially available culture test because it is new and requires additional validation testing in other studies.

Although the CDC recommends that patients use “FDA-approved” tests, Advanced Laboratory Services does not support this restriction because there are no FDA approved tests for Lyme Disease.

Sometimes diagnosis is achieved only by ruling out other diseases or illnesses.