Are there any conditions that prevent development of treponemal antibodies or make them undetectable? I’ve read weakened immunity and immunosuppressive medications can prevent antibody development, but I don’t know what immune deficiency looks like, or if it can be so mild so as to not be aware one has it. If one misses the antibody development window after initial infection, can they develop them later from the same infection? What about autoimmune disorders? Or hypothyroidism and its treatment?

I’m concerned my spouse’s negative treponemal blood test result (via 3 relatively recent blood donations) are false due to never developing detectable treponemal antibodies almost 20 years ago — explaining possible symptoms now but negative serology. I don’t know if he has immune issues, as he’s outwardly healthy aside from obesity (and possible rosacea) and has annual physicals and routine lab work. I don’t believe he’s taken any antibiotics in the last 20 years.