The problem with testing is they are not a accurate barometer for all vitamins and minerals. Some of these should be more concentrated within the cells, bones or other tissues so a simple blood test doesn't give you those values. Microbiologist and Endocrinologist have a better understanding of the chemical processes that take place when consuming food and the breakdown of the nutrients by the body for nutrition. So many times the body will rob p eter to pay paul when we are deficient and our absortion into bones, muscle and skin from the blood is compromised.