Methods of quantifying a N2-carboxyethyl-2′-deoxyguanosine (CEdG) levels in biological samples and comparing those levels to known normal levels can diagnose a number of disorders, including diabetes and cancer. Methods can also determine whether therapies for disorders are effective by measuring CEdG levels before and after treatment. Measurement of CEdG levels occurs using liquid chromatography electrospray ionization tandem mass spectrometry.
