differential diagnosis refers to a list of conditions that may be causing a person's symptoms. A doctor will use this list along with a number of factors, including medical history and the results of a physical examination and diagnostic tests to make an accurate treatment recommendation.

Mass Spectrometry (MS) is a technique for measuring the mass to charge ratio (m/z) of ions. From the mass and structure results, we can know about the biological function of the analyzed molecule. Tandem Mass Spectrometry (MS/MS) also shows chemical components at low or even very low concentrations in the analyzed mixture.