Rereading what I wrote and I'm not sure if you are fully understanding the question. There is a big difference between the many tests that can be done to blood. You would not want for example a place that only does drug tests to take your blood to screen for cancer. Blood sugar tests can be done with many home kits, but a screening for diabetes or vitamin deficiency should be done by a lab set up to do those. So to rephrase my question, what condition/requirement do you need to be tested for?