"Tick panels are a collective of tests for *antibodies* against several different tick-borne disease (TBD) organisms. Exactly which TBD are included in a panel will differ a bit from laboratory to laboratory. For example, ProtaTek Lab. includes tests for Ehrlichia canis, Babesia canis, Borrelia burgdorferii (Lyme disease), and Rickettsia rickettsii (Rocky Mountain Spotted Fever) antibodies in the "tick-borne panel" they list in their lab request form. (They are, however, flexible about substituting or adding tests for other TBD, as appropriate for the individual dog or the area where it lives.) The composition of tick-borne panels may be different at other laboratories.
"Note that as mentioned these are tests for antibodies. Once started, antibody production by the dog's immune cells does not fall away rapidly if treatment (e.g., antibiotics such as doxycycline) suppresses or eliminates the TBD organism that stimulated the start-up of production of the antibody.
"If the dog is producing antibodies to a TBD organism when the doxycycline is started it will still produce those antibodies (and test positive for them) for months to come--even if the doxycycline completely knocks the TBD bug out.
"PCR tests for the DNA of TBD organisms are something of a different story. These tests look for material (DNA) produced by the TBD organisms themselves rather than produced by the dog. Doxycycline can suppress the population of a TBD organism down to such low numbers that very very little of its DNA is in the blood--so little that the test fails to detect it.
"With PCR tests, to have a "comfortable" level of confidence in a negative result the sample should be taken before treatment is started or 2-3 weeks or more after treatment is ended."
"Note that as mentioned these are tests for antibodies. Once started, antibody production by the dog's immune cells does not fall away rapidly if treatment (e.g., antibiotics such as doxycycline) suppresses or eliminates the TBD organism that stimulated the start-up of production of the antibody.
"If the dog is producing antibodies to a TBD organism when the doxycycline is started it will still produce those antibodies (and test positive for them) for months to come--even if the doxycycline completely knocks the TBD bug out.
"PCR tests for the DNA of TBD organisms are something of a different story. These tests look for material (DNA) produced by the TBD organisms themselves rather than produced by the dog. Doxycycline can suppress the population of a TBD organism down to such low numbers that very very little of its DNA is in the blood--so little that the test fails to detect it.
"With PCR tests, to have a "comfortable" level of confidence in a negative result the sample should be taken before treatment is started or 2-3 weeks or more after treatment is ended."