Parasite serum antibody tests

Hi all,

I'm wondering how accurate are serum antibody tests for parasites?

i know from reading on here that stool tests are worthless...(the same is true for horse stool egg tests - always negative yet they exhibit wormy symptoms)

Does the body always produce antibodies for all the various types of parasites? Or is it a case of only sometimes?

Also , if it's a chronic infestation would antibody levels be affected?

I'm wanting a good test for toxo. Gondii, tapeworms, flukes..lyme too but i know that's a hit and miss scenario.

any advice really appreciated :-)