1. A method to quantify biomarkers, comprising providing a sample comprising a biomarker, the biomarker comprising one or more chemicals that are related to a physiological condition; using an X-ray fluorescence spectrometer to perform an X-ray fluorescence analysis on the sample to obtain spectral features derived from the biomarker; and quantifying the X-ray fluorescence signal of the biomarker; wherein the X-ray fluorescence spectrometer irradiates the sample with polychromatic X-rays, and wherein the sample has been stained using one or more stains selected from the set of chemical element that is not commonly found in the sample and a chemical comprising a chemical element that is not commonly found in the sample.