Are there any tests to make sure you are absorbing, distributing, metabolising, and excreting medications properly?

Medication Testing. The gold standard is to draw a series of blood tests after taking a dose and measuring the amount of the drug in each successive sample. If you were to plot the results on a graph, the goal would be for the graph to look like a normal bell shaped curve. However, one can only do this with drugs for which there is a blood test for.