The criteria used to establish a specific diagnosis. These criteria vary according to the nature of the disease and the purpose for which the case definition is used. When a specific pathogenic organism or pathological process is implicated, unequivocal diagnostic tests are usually available. With diseases such as multiple sclerosis, a scoring system is used, based on points for each of several diagnostic features, each of which is a common feature of the disease but none of which alone is sufficient for diagnosis. The syndromic approach to treatment is mostly used in surveillance and control of dangerous epidemics because screening and diagnostic tests are rarely if ever feasible. Moreover, it is more important to identify all possible, as well as probable, cases, especially with contagious diseases.
Subjects: Public Health and Epidemiology.