Bb is difficult to routinely isolate or culture from body tissues or fluids. Most health care providers look for antibodies against the spirochete in the blood to confirm the role of Bb as the causative agent of the patient's symptoms. Antibodies (or immunoglobulins) are small protein molecules produced by the immune system which "lock" on to or destroy specific microbial invaders or their products (Figure 10). Some patients with suspected neuro-borreliosis may also undergo a spinal tap to test for intrathecal antibody production.

Figure 10

Antibody Production IgM Indicates new infection First antibody produced Peaks at approximately 4 weeks Some individuals maintain IgM antibodies for many years; indicates a poor prognosis Does not cross placental barrier IgG Indicates older infection Are produced several weeks following infection Peaks at 6-8 weeks Crosses placental barrier

Antibody tests, while greatly improved, are less than optimal. These inadequacies can make it difficult to establish clearly whether or not Bb is truly involved in the patient's symptoms. In the first few weeks following infection, antibody tests are not reliable since the patient's immune system has not produced a high enough antibody titer for detection. Antibiotics given to the patient early in the infection may prevent the antibody level from reaching a detectable level even when Lyme disease bacterium is the cause of the patient's symptoms.

Because some tests cannot distinguish Lyme disease antibodies from antibodies of similar organisms, patients may test positive for Lyme disease, but their symptoms actually are caused by another bacterial or viral agent, e.g., a false-positive result. If the initial antibody test, the Enzyme-Linked Immunosorbent Assay (ELISA) is positive, another, more specific test (called the Western blot test) is performed to assist the health care provider in making a diagnosis.

The ELISA test is used to detect if Bb antibodies are present in the blood. Specifically, if either IgG or IgM antibodies are present, a western blot test is performed to identify specific IgM or IgG protein bands.

A false-negative test can occur if:

• the sample was obtained too soon after infection for antibody production
• antibiotics were given early in the disease and antibody production was aborted
• the test lacks sensitivity
• there was a laboratory error

A false-positive test can occur if:

• the test lacks specificity
• cross-reacting antibodies are present, i.e., syphilis

The following tests must be considered investigational, and their routine use in the clinical setting is NOT recommended:

• polymerase chain reaction — replication or amplification of bacterial DNA
• urinary antigen test — spirochete shed in urine
• borreliacidal antibody assay
• immune complex disruption
• T-cell proliferative responses

Other tests that may be conducted include:

• a Complete Blood Count (CBC)
• sedimentation rate
• liver enzyme assays
• radiological exams:
• X-rays
• CAT Scans
• MRIs
• SPECT Scans

Because the signs and symptoms of Lyme Disease mimic those of other illnesses, a differential diagnosis must be made. Diseases/conditions needing to be ruled out include:

• other tick-borne illnesses, such as ehrlichiosis and babeosis
• viral diseases such as mononucleosis and Epstein Barre viral disease
• other types of arthritis and joint injury
• stress-related illnesses such as chronic fatigue syndrome and myalgia
• multiple sclerosis