Biomarkers in migraine: their promise, problems, and practical applications.

Biomarkers are physical signs or laboratory measurements that "occur in association with a pathological process and have putative diagnostic and/or prognostic utility." Biomarkers hold considerable promise for understanding and intervening in the disease process of migraine. They may permit recognition of individuals at risk of developing migraine, improve the timing, accuracy, and precision of migraine diagnosis, and serve as indicators of treatment response and disease progression. Furthermore, they hold great promise for research. At the same time, there are important limitations to the use of biomarkers in migraine, including problems with validity, reliability, accuracy, and precision. Legal, ethical, and cost considerations are also important. This review describes the potential uses and limitations of biomarkers in migraine diagnosis, treatment, and research.