First, they agree that the health-care provider is the person who decides the clinical significance of an observed test result, a central argument in our thesis. In this context, a cutoff value for any test serves only as a guide, as it does for all of the supportive tests in medicine. Even though the authors of the letter would like to avoid the comparison, how would they interpret a hemoglobin value of 12.9 mg/dL in a 75-year-old man? Would they label the patient as having anemia? Or, for that matter, an arterial BP of 140/90 mm Hg in an 82-year-old woman? In both instances, the health practitioner uses the clinical context to determine whether the test result supports (and I emphasize the word support) a clinical diagnosis. Agreed-upon operational definitions are by and large used in studies to avoid subjective misclassification. In this regard, the simpler the definition, the more likely it will be accepted and shared.