Lyme disease tests measure Borrelia burgdorferi antibodies in the blood or in the cerebrospinal fluid (CSF) if there are signs and symptoms of central nervous system disease. These antibodies are produced by the body's immune system in response to exposure to Borrelia burgdorferi (B. burgdorferi), the bacterium that causes Lyme disease. Infected deer ticks or western black legged ticks transmit this bacterium to a person through a bite. The disease is most common in the spring and summer in the regions where these ticks live, such as the northeastern, mid-Atlantic, north-central, and western United States.
Lyme disease infection causes symptoms that may include a characteristic erythema migrans (EM) or "bulls-eye" rash that spreads from the site of the bite, fever, chills, headache, and fatigue. If left untreated, Lyme disease may progress to cause intermittent joint pain, meningitis, facial paralysis (Bell's palsy), weakness and numbness in the arms and legs, memory problems, and may rarely affect the heart or eyes.lyme_rash.jpg
It takes the body some time to begin producing B. burgdorferi antibodies. B. burgdorferi IgM (immunoglobulin M) antibodies are usually detectable in the blood about two to three weeks after exposure. IgM levels increase to maximum concentrations at about six weeks and then begin to decline. IgG (immunoglobulin G) antibodies are detectable several weeks after exposure, increase to maximum levels at about four to six months, and may remain at high levels for several years.
Combination of IgM and IgM/IgG testing has the potential to provide the earliest and the broadest time window for serological detection. Western blot confirmation is recommended for positive results.