Since it takes time for the immune system to respond to the infection and create antibodies, all antibody tests are less reliable in the early period after infection. As the infection progresses, virtually everyone with Lyme disease has a positive test result.
ELISA — The ELISA is usually the first test done for Lyme disease. The ELISA test is not very good (“sensitive”) at detecting antibodies to Lyme disease. Most people, despite being Lyme positive will come up negative on this test.
The screening ELISA may not be as accurate as some authorities suggest. A paper by CW Ang et al in 2011 noted “Remarkably, some immunoblots gave positive results in samples that had been tested negative by all eight ELISAs.” The test is not recommended until at least four weeks after exposure. Reference The C6-peptide ELISA is a more accurate form of the ELISA test though still not recommended. A positive ELISA must be followed up with a Western Blot.
Western blot — The second test, a Western blot, is done when the ELISA results are positive or equivocal (not clearly positive or negative); it is helpful in determining when the results of an ELISA test are falsely positive. The Western blot is more specific for B. burgdorferi than the ELISA because it identifies antigens individually; antigens are the parts of the Lyme disease bacteria that antibodies detect. The Western blot is typically reported as the number of antigens recognized (positive bands) out of the total tested. The greater the number of positive bands, the greater the chance that the patient has encountered the Lyme disease bacteria. Not all patients have anti- bodies at all times when tested. Antibodies are more commonly detected within the first year after infection, although re-infection may cause a significant rebirth of antibodies. At most, only 70% of patients have antibodies early, and the presence of antibodies alone does not make a diagnosis of disease. With Lyme Disease, there appears to be a cycling between IgM and IgG and thus, these are not accurate indicators of the length of time the infection has been present in most cases. It is critically important that one not look at the NEGATIVE or POSITIVE summary result of the Western Blot test. That criterion is based on CDC guidelines which many argue are not appropriate for Lyme disease. Instead, it is important to look at all of the bands and map those to the known Lyme-specific bands (those bands that represent evidence of serological exposure to Borrelia Burgdorferi). According to Dr. Charles Ray Jones, these are: 18 23 30 31 34 37 39 83 93 . Other doctors focus on 23-25, 31, 34, 39, 83-93 as the most specific bands. Additional information on the specific bands and what they mean can be found here.
The LYME DOT BLOT ASSAY (LDA) - looks for the presence of Lyme bacteria in urine. The assay specificity is better than 90%. The Reverse Western Blot is an antigen detection test in urine where the urine is exposed to rabbit antibodies for Borrelia Burgdorferi.
The PCR (Polymerase Chain Reaction) - a highly specific and sensitive test detects the presence of the DNA of the Lyme bacteria. The PCR test is often the only marker that is positive in all stages of Lyme disease. The test can be performed on blood, serum, urine, CSF and miscellaneous fluids/tissues. Unfortunately, Lyme bacteria like to “hide” in the body, therefore, PCR can often be negative.
CD-57 - We have all likely heard of people with HIV/AIDS getting their T-cell counts or CD-4 cell counts checked on a regular basis. Current information suggests that there is a similar population of NK (natural killer) cells called CD-57 cells that are known only to be suppressed in the presence of Lyme disease. Generally guidelines are that a score of < 20 indicates advanced or highly active Lyme disease. Scores of 20-60 are indicative of active Lyme disease where scores > 60 start to suggest that the Lyme infection is less active. A normal test result would be > 200. It is the opinion of some doctors that treatment is necessary until the CD-57 test score is 150 or above. The lower the result, the more likely a relapse if treatment is terminated. The test doesn't seem to provide consistent value for every patient. For more information on the CD-57 test from a recent article in the Public Health Alert, go here.
Cerebrospinal fluid tests — When a diagnosis of Lyme disease is uncertain and an individual has neurological symptoms, the cerebrospinal fluid (the fluid surrounding the brain and spinal cord) can be tested. It is a very painful test, and from what I understand, highly inaccurate. Cerebrospinal fluid is collected by inserting a needle into the lower back, below where the spinal cord ends. This procedure is called a lumbar puncture or LP.
Is the blood test always right? No. A German study has found that the early immune response undulates, so any early test is a “snapshot” which may be positive or negative.
Diagnosis is clinical and is based primarily on recognition of the typical symptoms of Lyme disease in a person who lives in a high-risk area. Doctors like to have hard evidence to back up their opinions, but testing is not an exact science: the tests for Lyme disease may sometimes be negative in cases where disease is actually present. Therefore, experienced doctors recommend that Lyme disease be diagnosed clinically, meaning they base the diagnosis on an evaluation of your risk and your symptoms.