One of the reasons to take a detailed history for all patients is to see the many historical influences on their health. These include environmental exposures such as pesticides, heavy metals, mold from water-damaged buildings, industrial waste or electric power lines near home or residence and much more. Often any one exposure can be handled by the body's incredible systems of detoxification. A lot of DNA is devoted to that.
However, when there have been multiple, extensive or long term environmental insults to the body, symptoms will be present. They manifest as many different diseases, eg, allergy, asthma, brain fog, joint and muscle pain, hormone disruptions, autoimmune disease, digestive problems and much more.
There are specialized tests, some from traditional labs, some from specialized ones that are more useful, especially when looking for the total body burden of toxins. If your body's 'elevator' has too many passengers, it is not going to work well. The passengers on that 'elevator' are allergies, toxins, infections and stress of all kinds. Lighten that total load and in almost every case, your elevator will start working better.