Yes, it is possible to test negative for coinfections and yet still have them. Remember clinical diagnosis is supported by postitive labs, but cannot be ruled out by negative labs (because there are so many more strains of these bugs than what they have tests for, and the immune system may not be able to generate detectable response to the bugs if it is suppressed by the bugs, and also sometimes the antibodies are all bound to bugs, thus no free antibodies to detect on the test).
My doctor believes I have Bart in addition to Lyme, even though Fry Labs found no evidence on the test or the blood smear. I have to agree, given that my symptoms do include some that can be caused by Bart (burning feet, etc.).
Chronic Lyme Disease, Gluten & Sulfite Sensitivity, Many Food/Inhalant/Medication Allergies & Intolerances, Asthma, Gut issues (dysmotility, non-specific inflammation), UCTD ("Secondary Lupus-Like Syndrome"), Osteoporosis, Anemia, Lymphopenia, intermittant Pancytopenia, chronic malabsorption/malnutrition, etc.; G-J Tube; Currently TPN-dependent.
Meds: Zofran, Pulmicort, Vitamin B12 Shots, Heparin (to flush PICC line).