Biomarkers and diagnostics are critical components in diagnosing a disease or pathogenic process, monitoring patients throughout treatment, and determining patient response to an exposure or therapy. Biomarkers and diagnostics are used in precision medicine to predict and monitor patient response to medicines, or to identify different sub-populations of patients who are most likely to benefit from pre-determined treatments. Any biological indicator that can be measured can be used as a biomarker. Biomarkers can be quantitative or qualitative in nature. In a yes/no analysis, qualitative biomarkers may be used to detect pathogenic processes, whereas quantitative biomarkers are used to detect pathogenic processes with a threshold effect.