Posted 2/25/2021 8:58 AM (GMT -7)
to my knowledge FISH and IFA tests are usually recommended as suitable tests for Babesia
however none of the available tests are perfect and there are many issues - mainly to do with sensitivity
as I understand it there are two main issues driving the lack of sensitivity ( or high false negative rate _ ie a high chance of getting a negative result despite being infected )
1- once chronic, these infections are characterized by extremely low levels of infected cells in the blood most of the time - often less than 1 in 1000 red blood cells in a sample are infected - this means that the chance of infection being detected in your sample, even if you are indeed infected, is much lower than we would like.
2- there are a number of babesia organisms out there in the wild and several/many can infect humans - however, the serological tests mentioned only look for antibodies to 2 main species ( microti and divergens ) - this means that even though you might be infected and producing detectable antibodies - the tests do not necessarily look for antibodies to teh species you are infected with and will therefore report a negative result.
this link gives a pretty good explanation
testing for pretty much all tick-borne pathogens is plagued by this kind of issues....
as a result, the two general approaches that people follow are:
1, diagnose by clinical signs symptoms, and history - usually via an experienced LLMD
2, run multiple tests - each using a different methodology so that you improve your overall chances of getting a positive result
there are of course issues with both of these approaches - but until better tests are developed - this is the state of play at present.