Leiddy Z. Alvarado presented on using metabolite profiling via nuclear magnetic resonance and mass spectrometry to analyze hundreds of small molecules in biological samples as an alternative method for the early detection of recurrent breast cancer. She explained that both NMR and MS are needed to analyze the samples and discussed the difference between sensitivity, which refers to correctly identifying people who have the disease, and specificity, which refers to correctly identifying people who do not have the disease.