Serology is the science that deals with the characterization of serum, the noncellular component of blood. Serum contains many valuable proteins, nucleotides, and other chemicals that aid the physiological functions of the body. Between 1900 and 1950, numerous scientific studies were performed to study the production of serum and its use in monitoring and controlling diseases. This period has been called the era of International Serology.
Serological markers are used to distinguish specific diseases in individuals. These markers are invaluable in the detection of some cancers, especially due to their potential in identifying the early stages of the disease, prior to the onset of symptoms.
CRITERIA IN ASSESSING SEROLOGICAL MARKERS
Several criteria are used to assess a serological method in a clinical laboratory, including sensitivity, specificity, and predictive value. Diagnostic sensitivity (Se) is the ability to correctly identify those who have a specific disease and is defined by the ratio of true positives over true positives and false negatives. Diagnostic specificity (Sp) is the ability of the test to correctly identify those who do not have the disease and is defined by the ratio of true negatives over true negatives and false positives. Both of these indexes measure the accuracy of assays using serological markers relative to an established and standard procedure. The predictive value (Pr) contains two components: a positive predictive value (Pp) and a negative predictive value (Pn); the former describes the likelihood that a positive test result represents a true positive and the later defines the likelihood that a negative result is truly negative. All the above definitions are described in Figure 1.
WENDY WANG, SUDHIR SRIVASTAVA, The Gale Group Inc., Macmillan Reference USA, New York,