Bartonella questions

“ recently I have recieved both serology and PCR for bart and both were negative (there was small IgG and the lab interepreted it as having had bart in the past,”

What I have been told by several Lyme docs is :
IgG can be an older but still an active infection and you can not use testing to gauge when you are in remission.

i have never seen any data on temperature and bartonella - so i do not think it is sensitive to heat in the same way that borrelia is.

standard serology ( eg ELISA type test looking for bartonella antibodies IgG or IgM) is likely only around 20% sensitive for chronic infections with bartonella ( i.e. only detects 20% of infected patients )
the UK NHS completely withdrew it for this reason in the last year or so.

standard PCR of blood for bartonella is not much better - well below 50% sensitivity - probably somewhere between 20 and 50% dependent on exact methodology

the best tests currently available for bartonella are expensive and often difficult to access
here are the best ones - in order of best performing first - but also highest cost first:

1, Galaxy diagnostics have a triple draw digital droplet PCR. they take 3 separate blood draws on different days to increase the change of getting some bacteria in the sample - each is first cultured - and then subjected to very sensitive PCR to maximise the chances of detecting bartonella - this is the leading technology currently available - and they have published a validation study that shows its around 50% sensitivity - but in reality the test likely performs much better than this. The scientist who founded the lab are highly respected researchers in the field with decades of published work on bartonella to their name and they are very careful not to over claim in all their work.
i have also spoken to the CEO - who is a highly qualified person with high integrity who is clearly doing something they believe in.
its very expensive - i think around $1700-1900 - but they hope the price will come down in time

2, Igenex have a multispecies western blot for bartonella that is serology - but uses many antigens from multiple species of bartonella to get a higher sensitivity - this is probably above 50% sensitive
i think this is also expensive - perhaps around $1000 - so less expensive that the Galaxy test - but also probably less sensitive and so still worth mentioning for another value vs performance option.

3, T-Labs is another advanced lab in the USA - they have a bartonella immuno-fluorescence based test that should also be highly sensitive - but is classed as research only - and accessed only through certain practitioners who partner with them.

finally, i am not quite at the stage of doing it right now, but, due to the lack of useful bartonella tests priced below around $1000 - i am considering setting up a UK based lab that performs thin blood smear testing via microscopy that can be used as a direct method (not reliant on antibodies) to detect bartonella and Babesia species.
this is not new technology - but an established World Health Organisation approved test method for detecting blood born pathogens.
i used this method to definitively diagnose my own bartonella infection.(see link in my signature for images of what to expect)

T-Lab also offers this type of test and uses it for both diagnosis and treatment progress tracking - but its a labour intensive test and requires the operators to be highly trained - and spend a lot of time on multiple slides -(rather than simply load a sample into an automated machine that spits out the results a few minutes later) so its rarely used today - despite the advantages.

this test can also detect other disease markers like platelet activation and platelet aggregation, lymphocyte activation, amyloid and fibrin deposits and red blood cell morphology changes ( all common in chronic bartonella, Babesia, Lyme patients and can give indications of treatment progress).

I did the igenix bart western blot and got a +. I don’t recall that specific test being $1000 but it wasn’t cheap either.

It’s also not much help when you’ve been treating for awhile to decide. I think OP has a good perspective here.