Lyme disease can cause a lot of symptoms and be related with other infections like candida and parasites. In some places corporate labs have lyme tests - altho they aren't always accurate if anything positive shows on a lyme test then that can be a clue right there.
Second - parawellness has found parasites in some people when other labs missed it - they do a stool and urine test that can be recieved and shipped back after taking it through delivery.
Third thing is heavy metals can also be a part these diseases so it is an option if it is affordable, the tests can be expensive sometimes and more likely alternative medicine doctors may do heavy metal tests when standard doctors might not.