- 1. The condition or state of being specific, of having a fixed relation to a single cause or to a definite result; manifested in the relation of a disease to its pathogenic microorganism, of a reaction to a certain chemical union, or of an antibody to its antigen or the reverse. 2. In clinical pathology and medical screening, the proportion of individuals with negative test results for the disease that the test is intended to reveal, i.e., true negative results as a proportion of the total of true negative and false-positive results. Cf.:sensitivity (2).- diagnostic s. the probability (P) that, given the absence of disease (D), a normal test result (T) excludes disease; i.e., P(T/D).- relative s. the s. of a medical screening test as determined by comparison with the same type of test ( e.g., s. of a new serological test relative to s. of an established serological test).- substrate s. the ability of an enzyme to recognize and bind its substrates, typically measured by the Vmax/Km or kcat/Km ratios.
* * *a) the condition of being peculiar to a particular individual or group of organisms <host \specificity of a parasite>b) the condition of participating in or catalyzing only one or a few chemical reactions <the \specificity of an enzyme>
* * *n.
* * *spec·i·fic·i·ty (spes″ĭ-fisґĭ-te) 1. the quality or state of being specific. 2. the conditional probability that a person not having a disease will be correctly identified by a clinical test, i.e., the number of true negative results divided by the total number of those without the disease (which is the sum of the numbers of true negative plus false positive results). Cf. sensitivity and predictive value.
Medical dictionary. 2011.