Lab tests are responsible for 70% of most diagnoses. They will show if blood cell counts are normal indicating possible infection, anemia or leukemia. Chemistry tests can tell if your kidney, liver, thyroid, pancreas and heart are functioning well. It’s very non-invasive, just a stick in the skin and they can tell mountains about the health of nearly every organ of the body. These are just the basic run of the mill tests. There are hundreds of other lab tests that help specify thousands of illnesses.