Not hard at all to see the infections in your blood with a little bit of knowledge and practice.
However, it is hard to get a lab to find them. The samples need to be observed at 1000x, oil immersion, which they rarely do in labs, unless specifically instructed.
They also need to look at each smear for a minimum of 20 - 30 minutes, sometimes longer before you find something...I can guarantee no lab does this.
In my samples, I don't see spirochetes until the sample has been sitting for 24 - 48 hours. Then they come out of the cells and start to be visible as they swim through the plasma. I don't know if any lab would leave your sample out for that long.
On top of that, lab techs simply aren't trained to spot "rare" infections like Babesia or Bartonella. They're trained to differentiate white blood cells and spot red blood cell malformations.
You can do your own microscopy for fairly cheap. Check out this thread:
www.healingwell.com/community/default.aspx?f=30&m=3753190