Points to consider when you are dealing with Lyme disease:
1. Prevention is very important including using insecticide (acaricides) in the endemic areas, using protective clothing, tick repellent, checking for ticks and taking a shower within two hours of being in the tick habitat.
2. It would take two weeks for Lyme IgM to become positive after development of erythema migrans and two to six weeks for IgG to become positive. With early treatment these test may never turn positive. Also these antibodies may remain positive for a long time despite successful treatment of Lyme disease and resolution of all of the presenting symptoms.
3. False positive Lyme testing can occur in 5% of the normal population with more false positivity seen with IgM than IgG. Western Blot should help as to rule out these as well as other false positive results caused by cross reacting antibodies.
4. PCR can help but it has both false positive and false negative results. PCR can not tell if there is active infection as it measures only the DNA of either live or dead spirochetes.
5. Urine antigen testing for Lyme and PCR of urine are useless.
6. The C6 testing that measures IgG to VlsE (Variable major protein-like sequence-expressed) sixth invariant region can be helpful along with traditional testing by increasing both sensitivity and specificity of these tests with IgG antibodies developing very early (within one week) in the disease process. This test is FDA approved but not endorsed by CDC. C6 testing also can detect both American and European species while the ELISA and Western Blot are optimized for the American species mostly.
7. Reinfection can also occur. This can be diagnosed with presence of new rash of erythema migrans. Repeating Lyme titers are not always helpful as previous titers from earlier infections may remain for a long time.